9장 유전양식.

Presentation on theme: "9장 유전양식."— Presentation transcript:

1 9장 유전양식

2 멘델의 법칙 © 2012 Pearson Education, Inc. 2

3 9.2 실험유전학은 수도원의 정원에서 시작되었다 유전(Heredity ) 형질들이 한 세대로부터 다음 세대로 전해지는 현상이다
유전(Heredity ) 형질들이 한 세대로부터 다음 세대로 전해지는 현상이다 유전학(Genetics) 유전에 대해 과학적으로 연구하는 학문이다 멘델(Gregor Mendel) 1860년대 유전학을 연구하기 시작 완두 실험에서 유전학 원리를 알아냈으며 Student Misconceptions and Concerns The authors note that Mendel’s work was published in 1866, seven years after Darwin published Origin of Species. Consider challenging your students to consider whether Mendel’s findings supported Darwin’s ideas. Some scientists have noted that Darwin often discussed the evolution of traits by matters of degree. Yet, Mendel’s selection of pea plant traits typically showed complete dominance, rather than the possibility for such gradual inheritance. Teaching Tips 1. In Module 9.2, the authors make the analogy between genes and playing cards, noting that each are shuffled but retain their original identity. This analogy may form a very useful reference point for your students and can be used later, as new principles of genetics are discussed. 2. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. © 2012 Pearson Education, Inc. 3

4 부모가 자손에게 “유전성 인자(heritable factor)”를 전달한다고 주장
1866년 멘델은 부모가 자손에게 “유전성 인자(heritable factor)”를 전달한다고 주장 유전성 인자(현재 유전자라 부름)는 여러 세대를 거치면서도 고유성을 잃지 않는다고 강조하였다 꽃의 색처럼 개체들마다 서로 다른 유전 특징을 특성(character)이라고 한다 한 가지 특성에 있어, 보라색이나 흰색 꽃처럼 서로 다른 특성을 형질(trait)이라고 한다 Student Misconceptions and Concerns The authors note that Mendel’s work was published in 1866, seven years after Darwin published Origin of Species. Consider challenging your students to consider whether Mendel’s findings supported Darwin’s ideas. Some scientists have noted that Darwin often discussed the evolution of traits by matters of degree. Yet, Mendel’s selection of pea plant traits typically showed complete dominance, rather than the possibility for such gradual inheritance. Teaching Tips 1. In Module 9.2, the authors make the analogy between genes and playing cards, noting that each are shuffled but retain their original identity. This analogy may form a very useful reference point for your students and can be used later, as new principles of genetics are discussed. 2. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. © 2012 Pearson Education, Inc. 4

5 멘델의 성공 비결 ? 1. 완두는 자가 교배 된다. → 멘델은 임의 대로 수정을 할 수 있었다. 2. 멘텔은 한 번에 많아야 두 가지 형질만을 선택하여 연구하였다. → 통제된 유전자 배경에서, 각 형질의 전달을 추적할 수 있었다. 3. 멘델이 선택한 형질은 단순 우성에 따라 나타난다. 1) 각 형질이 구별되는 두 가지 형태로 나타낸다. 2) 자손에서 우성만을 볼 수 있다. 4. 멘델은 link 되지 않은 형질을 관찰하였다. (행운 !!) 5. 멘델은 수 백번의 교배를 실시했고, 수천 개의 후세를 가려냈다.

6 그림 9.2C_s3 Mendel’s technique for cross-fertilization of pea plants (step 3)
6

7 그림 9.2D 그림 9.2D The seven pea characters studied by Mendel 7

8 R 유전자는 종자에의 starch 축적에 영향을 미친다.
저장한다 (→ 종자가 발아할 때 사용한다). starch/ glucose (포도당) 단위체로 형성된 복합체이다. 두 종류의 starch 1) amylose/ 300 개의 glucose가 직선으로 배열되어 있다. (1 →4 linkage) 2) amylopectine/ 1,000 여개의 glucose로 형성되며 가지를 갖고 있다. (1 →4 linkage, 1 →6 linkage)

9 ADP + sucrose <-> ADP-D-glucose + fructose + Pi
R 유전자는 Sucrose Synthase를 암호하고 있다. Sucrose Synthase ADP + sucrose <-> ADP-D-glucose + fructose + Pi - ADP-D-glucose를 amylose 사슬에 결합 (1 →4 linkage). * starch는 설탕 (sucrose)로부터 합성된다. rr의 완두는 RR이나 Rr의 완두보다 설탕을 효율적으로 starch로 전환시킬 수 없다. 따라서, 종자가 형성될 때 rr의 떡잎에 설탕의 농도가 상대적으로 RR이나 Rr보다 높다. → 생성과정에 있는 rr 종자에 보다 많은 물이 흡수된다. → 종자 생성의 마지막 단계는 건조 과정이다. → rr이 RR이나 Rr 보다 쭈굴 쭈굴 해진다.

10 순종(True-breeding )은 자가수정으로 부모와 모든 형질이 동일한 자손이 만들어질 때
순종(True-breeding )은 자가수정으로 부모와 모든 형질이 동일한 자손이 만들어질 때 두 개의 서로 다른 품종으로부터 나온 자손을 잡종(hybrid)이라고 한다 타가수정은 잡종화(hybridization) 혹은, 교배(cross)라고 한다 순종인 부모세대 식물을 P 세대(P generation )라 하고 하고, 잡종인 자손을 F1 세대라고 한다 F1 식물은 F2 세대를 만든다 Student Misconceptions and Concerns The authors note that Mendel’s work was published in 1866, seven years after Darwin published Origin of Species. Consider challenging your students to consider whether Mendel’s findings supported Darwin’s ideas. Some scientists have noted that Darwin often discussed the evolution of traits by matters of degree. Yet, Mendel’s selection of pea plant traits typically showed complete dominance, rather than the possibility for such gradual inheritance. Teaching Tips 1. In Module 9.2, the authors make the analogy between genes and playing cards, noting that each are shuffled but retain their original identity. This analogy may form a very useful reference point for your students and can be used later, as new principles of genetics are discussed. 2. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. © 2012 Pearson Education, Inc. 10

11 9.3 멘델의 ‘분리의 법칙’은 단일 특성의 유전을 설명한다
단성잡종교배(monohybrid cross) 한 가지 특성에만 차이가 있는 개체들간의 교배 멘델은 보라색 꽃 식물과 하얀색 꽃 식물간 단성잡종교배 실시하였다 F1 세대는 모든 식물이 보라색 꽃을 피움 F1 식물을 서로 교배하면 F2 세대에서는 ¾ 은 보라색, ¼ 은 흰색 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips 1. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. 2. Many students benefit from a little quick practice with a Punnett square. Have them try these crosses for practice: (a) PP  pp and (b) Pp  pp. 3. For students struggling with basic terminology, an analogy between a genetic trait and a pair of shoes might be helpful. A person might wear a pair of shoes in which both shoes match (homozygous), or less likely, a person might wear shoes that do not match (heterozygous). 4. Another analogy that might help struggling students is a pair of people trying to make a decision about where to eat tonight. One person wants to eat at a restaurant, the other wants to eat a meal at home. This (heterozygous) couple eats at home (the dominant allele “wins”). © 2012 Pearson Education, Inc. 11

12 그림 9.3A 그림 9.3A_s3 Crosses tracking one character (flower color) (step 3) 12

13 모든 보라색 F1 generation 세대가 ‘혼합가설’의 예측과는 다르게 연한 보라색 꽃을 만들지 않았다
모든 보라색 F1 generation 세대가 ‘혼합가설’의 예측과는 다르게 연한 보라색 꽃을 만들지 않았다 멘델은 다음을 설명해야 했다 왜 흰색 꽃이 F1 세대에서 사라지는 것처럼 보였는가? 이 흰색 꽃이 왜 F2 자손의 1/4에서 다시 나타났는가? 멘델은 완두의 다른 6가지 특성에 대해서도 동일한 유전양식을 관찰했다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips 1. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. 2. Many students benefit from a little quick practice with a Punnett square. Have them try these crosses for practice: (a) PP  pp and (b) Pp  pp. 3. For students struggling with basic terminology, an analogy between a genetic trait and a pair of shoes might be helpful. A person might wear a pair of shoes in which both shoes match (homozygous), or less likely, a person might wear shoes that do not match (heterozygous). 4. Another analogy that might help struggling students is a pair of people trying to make a decision about where to eat tonight. One person wants to eat at a restaurant, the other wants to eat a meal at home. This (heterozygous) couple eats at home (the dominant allele “wins”). © 2012 Pearson Education, Inc. 13

14 1. 대립유전자(alleles)는 유전자의 서로 다른 유형으로 서, 유전된 특성의 차이를 설명해준다
멘델이 세운 네 가지 가설 1. 대립유전자(alleles)는 유전자의 서로 다른 유형으로 서, 유전된 특성의 차이를 설명해준다 2. 각각의 특성에 대해서, 개체는 두 개의 대립유전자 즉, 한 부모로부터 하나씩 물려 받는다. 이때 대립유전자는 동일할 수도 있고, 다를 수도 있다 동형접합(homozygous) 유전형은 동일한 대립유전자를 갖는다 이형접합(heterozygous) 유전형은 서로 다른 대립유전자를 갖는다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips 1. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. 2. Many students benefit from a little quick practice with a Punnett square. Have them try these crosses for practice: (a) PP  pp and (b) Pp  pp. 3. For students struggling with basic terminology, an analogy between a genetic trait and a pair of shoes might be helpful. A person might wear a pair of shoes in which both shoes match (homozygous), or less likely, a person might wear shoes that do not match (heterozygous). 4. Another analogy that might help struggling students is a pair of people trying to make a decision about where to eat tonight. One person wants to eat at a restaurant, the other wants to eat a meal at home. This (heterozygous) couple eats at home (the dominant allele “wins”). © 2012 Pearson Education, Inc. 14

15 한 염색체 상에서 유전자가 차지하는 특정 위치이다 한 쌍의 상동 염색체에서 한 유전자의 대립유전자들은 동일한 좌위에 위치한다
좌위(locus, 복수는 loci) 한 염색체 상에서 유전자가 차지하는 특정 위치이다 한 쌍의 상동 염색체에서 한 유전자의 대립유전자들은 동일한 좌위에 위치한다 동형접합 개체는 상동염색체 상에 동일한 대립유전자를 갖고 있다 이형접합 개체는 상동염색체 위에 서로 다른 대립유전자를 갖고 있다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips 그림 9.4 can be of great benefit when introducing genetic terminology. For students struggling to think abstractly, such a visual aid may be essential when describing these features in lecture. © 2012 Pearson Education, Inc. 15

16 그림 9.4 그림 9.4 Three gene loci on homologous chromosomes 16

17 3. 우성 대립유전자(dominant allele) 만약 유전된 대립유전자가 다르고, 하나가 개체의 외형을 결정할 경우
3. 우성 대립유전자(dominant allele) 만약 유전된 대립유전자가 다르고, 하나가 개체의 외형을 결정할 경우 열성 대립유전자(recessive allele) 개체의 외형에 영향을 주지 않을 경우 *표현형(phenotype) 겉으로 나타나거나 표현되는 형 *유전자형(genotype) 형질의 유전적 구성이다. 동일한 표현형이 한 가지 이상의 유전자형에 의해 결정될 수 도 있다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips 1. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. 2. Many students benefit from a little quick practice with a Punnett square. Have them try these crosses for practice: (a) PP  pp and (b) Pp  pp. 3. For students struggling with basic terminology, an analogy between a genetic trait and a pair of shoes might be helpful. A person might wear a pair of shoes in which both shoes match (homozygous), or less likely, a person might wear shoes that do not match (heterozygous). 4. Another analogy that might help struggling students is a pair of people trying to make a decision about where to eat tonight. One person wants to eat at a restaurant, the other wants to eat a meal at home. This (heterozygous) couple eats at home (the dominant allele “wins”). © 2012 Pearson Education, Inc. 17

18 4. 분리의 법칙(law of segregation) 생식세포를 형성할 때 대립유전자 쌍이 서로 분리된다.
4. 분리의 법칙(law of segregation) 생식세포를 형성할 때 대립유전자 쌍이 서로 분리된다. 정자나 난자는 각각의 유전된 특성에 대해 한 가지 대립유전자만을 갖게 된다. 멘델의 가설은 또한 F2 세대에서의 3:1 비율을 설명해준다 F1 잡종은 모두 Pp 유전자형을 가지고 있으며 퍼네트 사각형(Punnett square)은 이들 생식세포가 합해질때 발생할 수 있는 네 가지의 가능한 대립유전자 조합을 보여준다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips 1. This early material introduces many definitions that are vital to understanding the later discussions in this chapter. Therefore, students need to be encouraged to master these definitions immediately. This may be a good time for a short quiz to encourage their progress. 2. Many students benefit from a little quick practice with a Punnett square. Have them try these crosses for practice: (a) PP  pp and (b) Pp  pp. 3. For students struggling with basic terminology, an analogy between a genetic trait and a pair of shoes might be helpful. A person might wear a pair of shoes in which both shoes match (homozygous), or less likely, a person might wear shoes that do not match (heterozygous). 4. Another analogy that might help struggling students is a pair of people trying to make a decision about where to eat tonight. One person wants to eat at a restaurant, the other wants to eat a meal at home. This (heterozygous) couple eats at home (the dominant allele “wins”). © 2012 Pearson Education, Inc. 18

19 그림 9.3B 그림 9.3B_s3 An explanation of the crosses in 그림 9.3A (step 3)
19

20 9.5 ‘독립의 법칙’은 두 가지 특성을 동시에 추적함으로써 밝혀졌다
양성잡종교배(dihybrid cross) 두 가지 서로 다른 특성을 가진 부모들의 교배 멘델이 수행한 양성잡종교배의 결과 : 부모세대: 둥글고 노란 콩  주름지고 초록색 콩 F1 세대: 모든 둥글고 노란 콩 F2 세대: 9/16은 둥글고 노란 콩 /16은 주름지고 노란 콩 3/16은 둥글고 초록색 콩 1/16은 주름지고 초록색 콩 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips Understanding dihybrid crosses may be the most difficult concept in this chapter. Consider spending additional time to make these ideas very clear. As the text indicates, dihybrid crosses are essentially two monohybrid crosses occurring simultaneously. © 2012 Pearson Education, Inc. 20

21 그림 9.5A 그림 9.5A Two hypotheses for segregation in a dihybrid cross 21

22 그림 9.5B 그림 9.5B Independent assortment of two genes in the Labrador retriever 22

23 특성들이 부모들과 다른 새로운 조합을 보이는지, 그리고 9:3:3:1 표현형 비율이 관찰되는지 설명해야 했다
멘델은 왜 F2 자손들에서 특성들이 부모들과 다른 새로운 조합을 보이는지, 그리고 9:3:3:1 표현형 비율이 관찰되는지 설명해야 했다 독립의 법칙(law of independent assortment) 한 가지 특성의 유전은 다른 특성의 유전에 영향을 주지 않는다. 양성잡종교배는 두 개의 단성잡종교배와 같다. Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips Understanding dihybrid crosses may be the most difficult concept in this chapter. Consider spending additional time to make these ideas very clear. As the text indicates, dihybrid crosses are essentially two monohybrid crosses occurring simultaneously. © 2012 Pearson Education, Inc. 23

24 9.6 유전학자는 검정교배를 이용하여 유전자형을 알아낸다
검정교배(testcross) 유전자형을 모르는 개체와 동형접합 열성인 개체의 교배 검정교배는 모르는 유전자형이 열성 대립유전자를 갖고 있는지를 알려준다 멘델은 자신이 얻은 식물이 순종의 유전자형인지 확인하기 위해 검정교배를 이용하였다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips Consider challenging your students to explain why a testcross of two black Labs of unknown genotypes might not reveal the genotype of each dog. (If both dogs are heterozygous, or homozygous, the results would reveal the genotypes because the offspring would either be three dark and one brown or all dark. But if one black Lab was homozygous and the other heterozygous, we could not determine which Lab has which genotype.) © 2012 Pearson Education, Inc. 24

25 그림 9.6 그림 9.6 Using a testcross to determine genotype 25

26 9.7 멘델의 법칙은 확률의 법칙을 따른다 멘델은 생식세포 형성 때, 대립유전자 쌍이 분리되고,
멘델은 생식세포 형성 때, 대립유전자 쌍이 분리되고, 수정 시에 다시 이들 대립유전자들이 쌍을 이루는 것은 확률에 영향을 받는다는 것을 알게 되었다 확률은 0에서 1 사이의 값을 갖는다 반드시 일어날 확률은 1이고 반드시 일어나지 않는 확률은 0이다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips Many students have trouble with the basic statistics that are necessary for many of these calculations. Give your students some practice. Consider having them work in pairs, each with a pair of dice (for large class sizes, this can be done in laboratories). Let them calculate the odds of rolling three sixes in a row and other possibilities. © 2012 Pearson Education, Inc. 26

27 그림 9.7 그림 9.7 Segregation and fertilization as chance events 27

28 특정사건이 일어날 확률은 사건이 일어날 수 있는 가능한 전체 결과로부터의 경우의 수이다
특정사건이 일어날 확률은 사건이 일어날 수 있는 가능한 전체 결과로부터의 경우의 수이다 두 개의 독립적인 사건이 일어날 가능성은 곱셈법칙을 이용해 결정한다. 곱셈법칙 (Rule of multiplication)은 독립적인 사건이 일어날 각각의 확률을 곱한 것이다 하나의 사건이 둘 또는, 그 이상의 서로 다른 방법으로 일어날 확률은 각각의 확률의 합과 같다. 이를 덧셈법칙(rule of addition)이라고 한다 Student Misconceptions and Concerns Students using Punnett squares need to be reminded that the calculations are expected statistical probabilities and not absolutes. We would expect that any six playing cards dealt might be half black and half red, but we frequently find that this is not true. This might be a good time to show how larger sample sizes increase the likelihood that sampling will reflect expected ratios. Teaching Tips Many students have trouble with the basic statistics that are necessary for many of these calculations. Give your students some practice. Consider having them work in pairs, each with a pair of dice (for large class sizes, this can be done in laboratories). Let them calculate the odds of rolling three sixes in a row and other possibilities. © 2012 Pearson Education, Inc. 28

29 9.8 현상의 이해: 가계도를 이용하면 사람의 유전형질을 알아낼 수 있다
우성대립형질 A와 열성대립형질 a에 대한 단순한 우성-열성 유전의 경우 열성 표현형은 항상 동형접합 열성유전자형(aa)으로부터 나온다. 우성 표현형은 동형접합 우성유전자형 (AA) 혹은 이형접합 유전자형 (Aa) 으로부터 모두 나올 수 있다 야생형(Wild-type trait) 자연계에 더 흔하게 나타나는것 을 말하며, 반드시 우성 대립유전자에 의한 형질이 아니다 Student Misconceptions and Concerns Students might think that dominant alleles are naturally (a) more common, (b) more likely to be inherited, and (c) better for an organism. The text notes that this is not necessarily true. However, this might need to be emphasized further in lecture. Teaching Tips Students seem to learn much from 그림 9.8b by analyzing the possible genotypes for the people whose complete genotype is not known. Consider challenging your students to suggest the possible genotypes for these people, perhaps during lecture. © 2012 Pearson Education, Inc. 29

30 가족 구성원의 유전자형을 추정하는데도 이용할 수 있다
사람 형질의 유전도 멘델법칙에 의한다 가계도(pedigree) 여러 세대에 걸쳐 가족 내 형질 유전을 보여준다 우성 혹은, 열성 유전을 표시한다 가족 구성원의 유전자형을 추정하는데도 이용할 수 있다 Student Misconceptions and Concerns Students might think that dominant alleles are naturally (a) more common, (b) more likely to be inherited, and (c) better for an organism. The text notes that this is not necessarily true. However, this might need to be emphasized further in lecture. Teaching Tips Students seem to learn much from 그림 9.8b by analyzing the possible genotypes for the people whose complete genotype is not known. Consider challenging your students to suggest the possible genotypes for these people, perhaps during lecture. © 2012 Pearson Education, Inc. 30

31 그림 9.8B 그림 9.8B A pedigree showing the inheritance of attached versus free earlobes in a hypothetical family 31

32 9.9 현상의 이해: 사람의 많은 유전질환이 단일 유전자에 의해 조절된다
사람의 유전질환 열성유전 질병이 나타나려면 두 개의 열성 대립유전자가 필요하다 이형접합체인 부모는 질병을 일으키는 대립유전자를 가진 보인자이다 유전될 확률은 근친간의 교배로 증가한다 우성 유전 질병이 나타나려면 하나의 우성 대립유전자가 필요하다 일반적으로 우성 치사 대립유전자는 그 집단에서 제거된다 Teaching Tips 1. The 2/3 fraction noted in the discussion of carriers of a recessive disorder for deafness often catches students off guard as they are expecting odds of 1/4, 1/2, or 3/4. However, when we eliminate the dd (deaf) possibility, as it would not be a carrier, we have three possible genotypes. Thus, the odds are based out of the remaining three genotypes Dd, dD, and DD. Consider adding this point of clarification to your lecture. 2. As a simple test of comprehension, ask students to explain why lethal alleles are not eliminated from a population. Several possibilities exist: a) The lethal allele might be recessive, persisting in the population due to the survival of carriers, or b) the lethal allele might be dominant, but is not expressed until after the age of reproduction. 3. Ask your class a) what the odds are of a person developing Huntington’s disease if a parent has this disease (50%) and b) whether they would want this genetic test if they were a person at risk. The Huntington Disease Society website, offers many additional details. It is a good starting point for those who want to explore this disease in more detail. © 2012 Pearson Education, Inc. 32

33 그림 9.9A 그림 9.9A Offspring produced by parents who are both carriers for a recessive disorder, a type of deafness 33

34 발생 초기에 죽음을 유발하는 대립유전자 치사유전자 (lethal allele) (수정과정, 종자 발생과정, 유식물 등)
- 사람의 경우, 유산된다. eg. Mexican Hairless 우성대립인자가 동형접합되면, 치사작용이 일어난다.

35 Table 9.9 Table 9.9 Some Autosomal Disorders in Humans 35

36 멘델 법칙의 변형 © 2012 Pearson Education, Inc. 36

37 9.11 불완전 우성으로 중간 표현형이 나온다 완전 우성(complete dominance) : 멘델의 완두콩 교배 시,
완전 우성(complete dominance) : 멘델의 완두콩 교배 시, 언제나 부모의 한 쪽과 같다 불완전 우성(incomplete dominance): F1 잡종의 외형이 부모의 두 가지 표현형의 중간형 어떤 대립유전자도 다른 대립유전자에 대해 우성일 수 없으며 두 대립 유전자가 다 표현된다 Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips 1. Incomplete dominance is analogous to a compromise, or a gray shade. The key concept is that both “sides” have input. Complete dominance is analogous to an authoritarian style, overruling others and insisting on things being a certain way. Although these analogies might seem obvious to instructors, many students new to genetics appreciate them. 2. Another analogy for cholesterol receptors is fishing poles. The more fishing poles you use, the more fish you can catch. Heterozygotes for hypercholesterolemia have fewer “fishing poles” for cholesterol. Thus, fewer “fish” are caught and more “fish” remain in the water. © 2012 Pearson Education, Inc. 37

38 그림 9.11A 그림 9.11A Incomplete dominance in snapdragon flower color 38

39 고콜레스테롤혈증(hypercholesterolemia) 이는 혈액내 콜로스테롤 수치가 위험할 정도로 높은 질환
사람에서 볼 수 있는 불완전 우성의 예 고콜레스테롤혈증(hypercholesterolemia) 이는 혈액내 콜로스테롤 수치가 위험할 정도로 높은 질환 이형접합의 경우는 콜레스테롤 수치는 최고치와 정상 수치의 중간 정도이다 Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips 1. Incomplete dominance is analogous to a compromise, or a gray shade. The key concept is that both “sides” have input. Complete dominance is analogous to an authoritarian style, overruling others and insisting on things being a certain way. Although these analogies might seem obvious to instructors, many students new to genetics appreciate them. 2. Another analogy for cholesterol receptors is fishing poles. The more fishing poles you use, the more fish you can catch. Heterozygotes for hypercholesterolemia have fewer “fishing poles” for cholesterol. Thus, fewer “fish” are caught and more “fish” remain in the water. © 2012 Pearson Education, Inc. 39

40 그림 9.11B 그림 9.11B Incomplete dominance in human hypercholesterolemia
40

41 9.12 다수의 유전자가 집단에서 두 개 이상의 대립유전자를 갖는다
복대립유전자 (multiple alleles)* * 한 유전자에 여러 개의 대립유전자가 있을 때. DNA의 염기서열의 변화로 새로운 대립유전자가 생길 수 있다. Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips 1. Students can think of blood types as analogous to socks on their feet. You can have socks that match, a sock on one foot but not the other, you can wear two socks that do not match, or you can even go barefoot (type O blood)! Developed further, think of Amber (A) and Blue (B) socks. Type A blood can have an Amber sock with either another Amber sock or a bare foot (or “zero” sock). Blue socks work the same way. One amber and one blue sock represent the AB blood type. No socks, as already noted, represent type O. 2. Consider specifically comparing the principles of codominance (expression of both alleles) and incomplete dominance (expression of one intermediate trait). Students will likely benefit from this direct comparison. © 2012 Pearson Education, Inc. 41

42 토끼털 색을 결정하는 4 개의 대립형질 c (항상 열성), ch (c 보다는 우성), cch (ch 보다는 우성), C (다른 어떤 대립형질보다 우성)

43 e.g 사람의 ABO식 혈액형 표현형은 하나의 유전자에 대해 3개의 대립유전자를 갖는다
e.g 사람의 ABO식 혈액형 표현형은 하나의 유전자에 대해 3개의 대립유전자를 갖는다 - 네 가지 종류의 혈액형 유형 A, B, AB, O는 세 개의 대립유전자 조합에 의한다 - 이형접합 개체들의 경우, A와 B 대립유전자는 둘 다 표현되는 공동우성(codominance)이다 공동우성의 경우 어떤 대립유전자도 다른 대립유전자에 대해 우성일 수 없다 두 대립유전자의 표현은 이형 접합체에서 별개의 표현형으로 관찰된다 공동우성은 AB 혈액형에서 관찰된다 Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips 1. Students can think of blood types as analogous to socks on their feet. You can have socks that match, a sock on one foot but not the other, you can wear two socks that do not match, or you can even go barefoot (type O blood)! Developed further, think of Amber (A) and Blue (B) socks. Type A blood can have an Amber sock with either another Amber sock or a bare foot (or “zero” sock). Blue socks work the same way. One amber and one blue sock represent the AB blood type. No socks, as already noted, represent type O. 2. Consider specifically comparing the principles of codominance (expression of both alleles) and incomplete dominance (expression of one intermediate trait). Students will likely benefit from this direct comparison. © 2012 Pearson Education, Inc. 43

44 그림 9.12 그림 9.12 Multiple alleles for the ABO blood groups 44

45 상위성 (epistasis) 한 유전자의 발현을 숨기거나 (masking), 다른 유전자 발현에 영향을 미치는 것. 서로 다른 두 유전자 사이에서 일어나는 숨김 현상. eg. 사람의 ABO 혈액형 적혈구 세포표면의 탄수화물A와 B (항원)는 세포표면에 당단백질*이 존재해야만 부착될 수 있다. * H 유전자의 산물

46 9.13 하나의 유전자가 여러 표현형에 영향을 미칠 수 있다
다면발현(Pleiotropy)은 하나의 유전자가 여러 특징에 영향을 준다 겸상적혈구증(Sickle-cell disease)은 사람에서 볼 수 있는 다면발현의 한가지 예이다. 생성되는 헤모글로빈의 유형과 적혈구 모양에 영향을 미친다 빈혈을 일으키고 기관에 손상을 주며 겸상적혈구 대립유전자와 정상적혈구 대립유전자는 공동우성*이다 겸상적혈구증 보인자는 말라리아에 저항성이 있다 Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips The American Sickle Cell Anemia Association’s website, is a good place to find additional details. © 2012 Pearson Education, Inc. 46

47 그림 9.13B 그림 9.13B Sickle-cell disease, an example of pleiotropy 47

48 9.14 여러 유전자가 하나의 특성에 영향을 미칠 수 있다
다인자유전(polygenic inheritance) : 두 개 혹은, 두 개 이상의 유전자들이 한가지 표현형 특성에 부가적인 효과를 주는 현상 예: 사람의 피부색 Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips 1. Polygenic inheritance makes it possible for children to inherit genes to be taller or shorter than either parent. Similarly, skin tones can be darker or lighter than either parent. The environment also contributes significantly to the final phenotype for both of these traits. 2. The authors note that polygenic inheritance is the converse of pleiotropy. This is worth noting in lecture as these concepts are discussed. We often remember concepts better when they are contrasted in pairs. © 2012 Pearson Education, Inc. 48

49 그림 9.14 그림 9.14 A model for polygenic inheritance of skin color 49

50 9.15 환경은 여러 특성에 영향을 미친다 많은 특성들은 유전과 환경의 조합에 의한다.
많은 특성들은 유전과 환경의 조합에 의한다. 피부색은 햇볕에의 노출에 영향을 받는다. 암과 같은 질병에 걸릴 위험도는 유전 및 환경 요소와 연관이 있다. 일란성쌍둥이도 약간의 차이를 보인다. Student Misconceptions and Concerns 1. After reading the preceding modules, students might expect all traits to be governed by a single gene with two alleles, one dominant over the other. Modules 9.11–9.15 describe deviations from simplistic models of inheritance. 2. As these variations of Mendel’s laws are introduced, students are likely to get confused and become uncertain about the prior definitions. Consider keeping a clear definition of these different patterns of inheritance available for the class to refer to as new patterns are discussed (perhaps as a handout for student reference). 3. As your class size increases, the chances increase that at least one student will have a family member with one of the genetic disorders discussed. Some students may find this embarrassing, but others might have a special interest in learning more about these topics, and may even be willing to share some of their family’s experiences with the class. Teaching Tips 1. The authors note that polygenic inheritance is the converse of pleiotropy. This is worth noting in lecture as these concepts are discussed. We often remember concepts better when they are contrasted in pairs. 2. As the authors are careful to note, although genetics and the environment both contribute to the final phenotypes, only the genetic factors are inherited. This distinction is important to understanding the limitations of Lamarck’s mechanisms of evolution. If you will address principles of evolution soon after this chapter, this may be an important distinction to reinforce in lecture. References to tattoos and piercing may also help to distinguish between environmental influences and inheritance. Students with tattoos will not produce children born with tattoos! *유전적 영향만 유전된다 © 2012 Pearson Education, Inc. 50

51 유전자 발현에 대한 환경적인 영향 eg. 히말라야산 토끼 토끼의 귀, 코, 발끝, 꼬리 부분은 복부보다 차갑다
→ 검은 색을 띄고있다. 온도는 모피 색을 결정하는 색소분자의 양적분포에 영향을 미친다.

52 표현형 묘사 (phenocopy) 유전에 의해 일어난 것이 아니라, 환경의 영향으로 나타난 표현형

53 유전에 대한 염색체 원리 © 2012 Pearson Education, Inc. 53

54 염색체 - ‘끊이지 않고 길게 연결된 DNA 가닥과 여러 종류의 단백질이 모여 형성된 복합체’ 1. 염색체의 구조와 분류
1) 각각의 종은 특정한 수의 염색체를 갖는다. * 그 수가 생물의 복잡성이나, 두 종간의 근접성을 반영하지 않는다. eg. 모기 6 개, 벼와 소나무 24 개, 개 78 개, 잉어 104 개 2) 염색체의 염색 염료들은 염색체 마다 다른 밴드 pattern를 나타낸다. 이질염색질 (heterochromatin)/ 반복서열이 많고, 단단히 감긴 DNA에 염기가 결합된다. → 진하게 염색된다. 진정염색질 (euchromatin)/ 단일서열이 더 많고, 더 느슨하게 감겨진 DNA에 염기가 결합 된다. → 밝게 염색된다.

55 그림 9.1.생명과학길라잡이, 6판, 라이프사이언스 이질염색질 (heterochromatin)/ 말단소립 (telomere)과 동원체 (centromere)를 포함하고 있다. 염색체 구조의 견고성을 유지하는데 관여한다. 진정염색질 (euchromatin)/ 단백질을 암호하는 유전자가 많고, 느슨한 꼬임으로 정보를 이용하기 쉽다.

56 동원체 위치에 의한 염색체 분류 동원체(centromere) 반복적인 DNA 서열로 이루어진, 수축된 부위로 체세포분열시 방추사에 붙는다. 그림 9.2.생명과학길라잡이, 6판, 라이프사이언스

57 2. 인공염색체 세포 내에서 독립된 염색체로서 기능을 하고 염색체의 기본 구조를 갖고 있는 재조합 DNA 분자 1) ‘ 염색체를 구성하는 데 필요한 최소 구성 단위는 무엇인가? ’ 두 가지 접근 방법 - 현존하는 염색체를 줄여가며 분석한다. - DNA 조각으로부터 새로운 염색체를 만들어 나가면서, 필요한 부위를 발견한다. eg. 말단소립, DNA 복제가 시작되는 복제시점, 동원체

58 2) 염기서열 결정에 사용

59 9.16 염색체의 움직임으로 멘델의 법칙을 설명한다 유전에 대한 염색체 이론은 유전자는 염색체 상의 특정 좌위(위치)에 있다.
유전에 대한 염색체 이론은 유전자는 염색체 상의 특정 좌위(위치)에 있다. 감수분열 과정 중, 염색체들이 분리되고 독립적으로 분배된다 Student Misconceptions and Concerns This section of the chapter relies upon a good understanding of the chromosome-sorting process of meiosis. If students were not assigned Chapter 8, and meiosis has not otherwise been addressed, it will be difficult for students to understand the chromosomal basis of inheritance or linked genes. Teaching Tips 그림 9.16 requires an understanding of meiosis and the general cell cycle from Chapter 8. Students may need to be reminded that chromosomes are duplicated in the preceding interphase, as indicated in the first step. Furthermore, students may not initially notice that this diagram represents four possible outcomes, not stages of any one meiotic cycle. © 2012 Pearson Education, Inc. 59

60 멘델의 법칙은 감수분열 시 염색체 분리와 서로 관련이 있다 - The law of segregation
멘델의 법칙은 감수분열 시 염색체 분리와 서로 관련이 있다 - The law of segregation 분리의 법칙은 제 1 감수분열 후기에 상동염색체의 분리에 따른다 (그림 9.16의 긴 염색체의 상동염색체 쌍의 운명) The law of independent assortment which states that each pair of alleles sorts independently of other pairs of alleles during gamete formation 독립의 법칙은 제 1 감수분열 중기에 두 가지 방법의 염색체 배열에 따른다 (그림 9.16의 긴 염색체와 짧은 염색체 두 쌍(비상동염색체)의 운명) Student Misconceptions and Concerns This section of the chapter relies upon a good understanding of the chromosome-sorting process of meiosis. If students were not assigned Chapter 8, and meiosis has not otherwise been addressed, it will be difficult for students to understand the chromosomal basis of inheritance or linked genes. Teaching Tips 그림 9.16 requires an understanding of meiosis and the general cell cycle from Chapter 8. Students may need to be reminded that chromosomes are duplicated in the preceding interphase, as indicated in the first step. Furthermore, students may not initially notice that this diagram represents four possible outcomes, not stages of any one meiotic cycle. © 2012 Pearson Education, Inc. 60

61 그림 9.16 그림 9.16_4 The chromosomal basis of Mendel’s laws (Punnett square) 61

62 9.17 과학적 발견: 동일 염색체상에 있는 유전자들은 함께 유전되는 경향이 있다
베이트슨(Bateson)과 퍼네트(Punnett) F2 세대에서 9:3:3:1 비율을 보이지 않는 식물을 연구하여 그 결과 연관유전자*(linked gene)를 발견하였다. *동일한 염색체 상에 서로 가깝게 위치하며, 함께 유전되려는 경향이 있다. 일반적으로 멘텔의 법칙을 다르지 않는다. Student Misconceptions and Concerns This section of the chapter relies upon a good understanding of the chromosome-sorting process of meiosis. If students were not assigned Chapter 8, and meiosis has not otherwise been addressed, it will be difficult for students to understand the chromosomal basis of inheritance or linked genes. Teaching Tips Building on the shoe analogy developed in Chapter 8, linked genes are like a shoe and its shoelaces. The two are usually transferred together but can be moved separately under special circumstances. © 2012 Pearson Education, Inc. 62

63 그림 9.17 그림 9.17 The experiment revealing linked genes in the sweet pea
63

64 9.18 과학적 발견: 교차에 의해 대립유전자들의 새로운 조합이 만들어진다
9.18 과학적 발견: 교차에 의해 대립유전자들의 새로운 조합이 만들어진다 상동염색체들 사이의 교차로 인해 새로운 조합의 대립유전자들을 갖는 생식세포가 만들어진다 연관된 대립유전자들은 교차에 의해 분리되어 재조합된 생식세포들을 형성한다 재조합체의 비율을 재조합빈도(recombination frequency )라고 한다 Student Misconceptions and Concerns 1. This section of the chapter relies upon a good understanding of the chromosome-sorting process of meiosis. If students were not assigned Chapter 8, and meiosis has not otherwise been addressed, it will be difficult for students to understand the chromosomal basis of inheritance or linked genes. 2. The nature of linked genes builds upon our natural expectations that items that are closely together are less likely to be separated. Yet, students may find such concepts initially foreign. Whether it is parents holding the hands of children or people and their pets, we generally know that separation is more likely when things are farther apart. Teaching Tips 1. Crossing over (from Chapter 8) is like randomly editing out a minute of film from two movies and swapping them. Perhaps the fifth minute of Bambi is swapped for the fifth minute of Avatar. Clearly, the closer together two frames of film are, the more likely they are to move or remain together. 2. Challenge students to explain why Sturtevant and Morgan studied the genetics of fruit flies. As the text notes, their small size, ease of care, and ability to produce several generations in a matter of weeks or months were important factors. © 2012 Pearson Education, Inc. 64

65 그림 9.18C 그림 9.18C A fruit fly experiment demonstrating the role of crossing over in inheritance 65

66 그림 9.18A 그림 9.18A Review: the production of recombinant gametes 66

67 9.19 유전학자들은 교차의 결과를 이용해 유전자 지도를 만든다
재조합빈도를 조사함으로써, 모건(Morgan )과 그의 제자들은 한 염색체 상에 있는 유전자들의 거리가 멀수록 이들 사이에서 교차가 일어날 곳(point)이 더 많다는 것을 발견했다 재조합빈도 염색체에 있는 유전자들의 상대적인 위치를 파악하는데 쓰일 수 있다 Student Misconceptions and Concerns 1. This section of the chapter relies upon a good understanding of the chromosome-sorting process of meiosis. If students were not assigned Chapter 8, and meiosis has not otherwise been addressed, it will be difficult for students to understand the chromosomal basis of inheritance or linked genes. 2. The nature of linked genes builds upon our natural expectations that items that are closely together are less likely to be separated. Yet, students may find such concepts initially foreign. Whether it is parents holding the hands of children or people and their pets, we generally know that separation is more likely when things are farther apart. Teaching Tips 1. Crossing over (from Chapter 8) is like randomly editing out a minute of film from two movies and swapping them. Perhaps the fifth minute of Bambi is swapped for the fifth minute of Avatar. Clearly, the closer together two frames of film are, the more likely they are to move or remain together. 2. Challenge students to explain why Sturtevant and Morgan studied the genetics of fruit flies. As the text notes, their small size, ease of care, and ability to produce several generations in a matter of weeks or months were important factors. © 2012 Pearson Education, Inc. 67

68 그림 9.19A 그림 9.19A Mapping genes from crossover data 68

69 교차율을 이용한 지도(linkage map) 작성
두 유전자가 가까이 위치하고 있다면, 두 유전자 사이에 유전자의 재조합 (교차)이 일어 날 수 없다. eg. 1 cm (centimorgans) 1 cm (= 1Mb) 100 개의 감수분열 산물 중 1 개에서 유전자 조합이 일어날 경우

70 성염색체와 성연관유전자 © 2012 Pearson Education, Inc. 70

71 9.20 염색체는 여러 생물종의 성별을 결정한다 동물의 대다수는 한 쌍의 성염색체(sex chromosome)를 가지고 있다
동물의 대다수는 한 쌍의 성염색체(sex chromosome)를 가지고 있다 성염색체는 X와 Y로 나타내며 개인의 성을 결정한다 포유류의 경우 수컷은 XY 성염색체 암컷은 XX 성염색체 Y 염색체에는 정소의 발달에 관여하는 유전자들이 있다 Y 염색체가 없으면 난소가 발달한다 Teaching Tips As the text notes, in crocodilians and many turtles, sex is not genetically determined. Instead, the incubation temperature of the eggs determines an animal’s sex. Students may enjoy researching this unique form of sex determination, often identified as TSD (temperature-dependent sex determination). © 2012 Pearson Education, Inc. 71

72 메뚜기, 바퀴벌레, 그 외 여러 곤충들은 X-O 체계로 O는 성염색체가 없음을 나타내며 암컷은 XX 수컷은 XO
메뚜기, 바퀴벌레, 그 외 여러 곤충들은 X-O 체계로 O는 성염색체가 없음을 나타내며 암컷은 XX 수컷은 XO 특정 어류와 나비, 새들의 경우 성염색체는 Z와 W 수컷은 ZZ 암컷은 ZW Teaching Tips As the text notes, in crocodilians and many turtles, sex is not genetically determined. Instead, the incubation temperature of the eggs determines an animal’s sex. Students may enjoy researching this unique form of sex determination, often identified as TSD (temperature-dependent sex determination). © 2012 Pearson Education, Inc. 72

73 일부 개체에는 성염색체가 전혀 없다 벌의 경우, 염색체 수에 의해 성이 결정된다 암컷은 이배체이고 수컷은 반수체이다
일부 개체에는 성염색체가 전혀 없다 벌의 경우, 염색체 수에 의해 성이 결정된다 암컷은 이배체이고 수컷은 반수체이다 Teaching Tips As the text notes, in crocodilians and many turtles, sex is not genetically determined. Instead, the incubation temperature of the eggs determines an animal’s sex. Students may enjoy researching this unique form of sex determination, often identified as TSD (temperature-dependent sex determination). © 2012 Pearson Education, Inc. 73

74 몇몇 파충류는 발달 시기 중 특정 기간에 알이 품어진 온도에 의해 배아가 수컷이 될지 암컷이 될지 결정된다
일부 동물의 경우, 환경의 온도가 성을 결정한다 몇몇 파충류는 발달 시기 중 특정 기간에 알이 품어진 온도에 의해 배아가 수컷이 될지 암컷이 될지 결정된다 따라서 지구의 온도변화는 이러한 종의 성 비율에 영향을 줄 것이다 Teaching Tips As the text notes, in crocodilians and many turtles, sex is not genetically determined. Instead, the incubation temperature of the eggs determines an animal’s sex. Students may enjoy researching this unique form of sex determination, often identified as TSD (temperature-dependent sex determination). © 2012 Pearson Education, Inc. 74

75 9.21 성연관유전자는 독특한 유전양식을 나타낸다 성연관유전자(Sex-linked gene)는 성염색체 위에 위치한다
성연관유전자(Sex-linked gene)는 성염색체 위에 위치한다 e.g. 초파리 흰색 눈 유전은 X 연관 열성 형질을 보여준다 Student Misconceptions and Concerns The prior discussion of linked genes addresses a different relationship than the use of the similar term sex-linked genes. Consider emphasizing this distinction for your students. Teaching Tips An analogy can be drawn between sex-linked genes and the risk of not having a backup copy of a file on your computer. If you only have one copy, and it is damaged, you have to live with the damaged file. Females, who have two X chromosomes, thus have a “backup copy” that can function if one of the sex-linked genes is damaged. © 2012 Pearson Education, Inc. 75

76 red-eyed female crossed with a white-eyed male a homozygous,
a red-eyed male 그림 9.21B A homozygous, red-eyed female crossed with a white-eyed male 76

77 red-eyed female crossed with a white-eyed male
a heterozygous, red-eyed female crossed with a white-eyed male 그림 9.21D A heterozygous female crossed with a white-eyed male 77

78 9.22 현상의 이해: 성연관 유전질환은 주로 남성에게서 나타난다
사람의 대부분의 성연관 질환은 열성 대립유전자에 의하여 일어난다. 거의 남성에게서 볼 수 있다. 자신의 어머니로부터 X 연관 열성 대립유전자를 물려받는 남성은 질병을 갖게 된다 여성의 경우 양 부모로부터 모두 대립유전자를 물려받아야 질병에 걸리게 된다 Student Misconceptions and Concerns The likelihood that at least some students in larger classes are color-blind is very high. Some of these students might find this interesting and want to discuss it further. However, others might be embarrassed and not wish to self-identify. Teaching Tips 1. Female hemophiliacs are very rare because both X chromosomes would need to have the recessive trait. Although very unlikely, female hemophiliacs are known. Students may enjoy searching for details of these rare cases. For additional information about hemophilia, consider visiting the website of the National Hemophilia Foundation at 2. Hemophilia and other genetic diseases may also result from spontaneous mutations in a family with no known history of the disease. Although rare, this possibility should always be considered when tracing the history of an inherited disease. © 2012 Pearson Education, Inc. 78

79 혈우병(hemophilia) : 혈액 응고에 필요한 하나 또는 그 이상의 단백질이 결핍된 것으로 과도한 출혈이 특징이다
열성이며 성연관인 질환은 혈우병(hemophilia) : 혈액 응고에 필요한 하나 또는 그 이상의 단백질이 결핍된 것으로 과도한 출혈이 특징이다 적록 색맹(red-green color blindness) : 눈에 있는 빛을 감지하는 세포들이 기능을 하지 못한다 뒤센 근위축증(Duchenne muscular dystrophy) : 근육이 점점 약화되고 조절기능이 상실되었다 Student Misconceptions and Concerns The likelihood that at least some students in larger classes are color-blind is very high. Some of these students might find this interesting and want to discuss it further. However, others might be embarrassed and not wish to self-identify. Teaching Tips 1. Female hemophiliacs are very rare because both X chromosomes would need to have the recessive trait. Although very unlikely, female hemophiliacs are known. Students may enjoy searching for details of these rare cases. For additional information about hemophilia, consider visiting the website of the National Hemophilia Foundation at 2. Hemophilia and other genetic diseases may also result from spontaneous mutations in a family with no known history of the disease. Although rare, this possibility should always be considered when tracing the history of an inherited disease. © 2012 Pearson Education, Inc. 79

80 Hemophilia in the royal family of Russia
80

81 9.23 Y 염색체는 남성의 선조(ancestry)에 대한 단서를 제공한다
Y 염색체는 돌연변이를 제외하면, 완전한 형태 그대로 아버지로부터 아들로 전해진다. e.g. 2003년 중앙아시아에 살고 있는 남성 중, 약 8%*의 Y 염색체에 유전적 유사성이 있음을 발견 *1,600 만명의 남성이 가진 특이한 염색체가 1,000년 전의 칭기스칸에서 유래되었다고 추정 Teaching Tips Like the Y chromosome, mitochondrial DNA (mtDNA) can be used to trace maternal ancestry (because mitochondria are characteristically inherited from the egg). For a fee, several commercial groups offer to provide information about a person’s ancestry based upon genetic samples. Such groups can be found by searching the Internet using the keywords “genetic ancestry.” © 2012 Pearson Education, Inc. 81