Chapter 12 Chromosomes & Inheritance

Name: ______Period: ______

Chapter 12 Chromosomes & Inheritance

Section 12-1 Sex Determination

1. Are the chromosomes in male & female fruit flies the same? Explain.
2. What did Morgan name the 2 chromosomes in the non-identical pair?
3. Morgan hypothesized that the non-identical pair were the ______chromosomes.
4. All other chromosomes except X and Y are called ______.
5. What is the genotype for males? Females?
6. When male & female fruit flies are crossed, what percent of the offspring will be male? Female?
7. Because the X chromosome was much bigger than the Y chromosome, what did Morgan hypothesize?
8. Genes on the X chromosome are ______genes.
9. What is meant by sex linkage?
10. What are linkage groups?
11. What is the effect of crossing-over on genes?
12. Do genes that are close together or far apart get crossed over more often?
13. What is a chromosome map?
14. How is one map unit determined?
15. What is germ cell mutation & what is its effect?
16. What are somatic mutations & can they be passed on to offspring?
17. What are lethal mutations?
18. What are chromosome mutations?
19. Name & describe 4 types of chromosome mutations.
20. What are gene mutations?
21. What are point mutations?
22. What are substitutions & give an example of a disease caused by this type of gene change?
23. What are frame shift mutations?

Section 12-2 Human Genetics

1. What is a pedigree?
2. Write the symbol that would appear on a pedigree for each of the following:

a.  Male carrier?

b.  Male with trait?

c.  Female carrier?

d.  Female with trait?

1. Name several single allele traits (both dominant & recessive).
2. Name 3 sex-linked traits.
3. What are polygenic traits and name four.
4. What influences the expression of a sex-influenced trait?
5. Name & describe 2 types of nondisjunction.
6. What causes Down syndrome?
7. When would genetic screening be useful?
8. What is amniocentesis?
9. What disease is genetically screened for immediately after birth in the U.S.?