Download SI Bio 211

1. Sex Chromosomes
Label if the following are male or female.
XY
______
XX
______
XXY ______
Name an example of a sex-linked trait.
Define barr body:
XYY ______
What type of mutation causes XXY, XYY, and XXX?
XXX ______
X
______
2. Color-blindness is a sex-linked recessive trait. A color blind male marries a female who is not color blind.
When they have children, half of their sons have color-blindness and half of their daughters have
colorblindness. What is the genotype of the parents and of the children? Show the cross. Colorblind allele is
represented as XC and normal allele is represented as X whereas in male Y chromosome is represented as Y.
3. What happens if the male doesn’t have color-blindness while the female is color-blinded? Show the cross.
4. Label the mutations.
ABCD-EFG
ASDF-JKL
GHJKL-MN
ABCCD-EFG
ADF-JKL
JHGKL-MN
ERTYU-IO
XCVBN-M
XCVYU-IO
ERTBN-M
BIOLO-GY
LKJH-GFD
MNBV-CX
WERT-YUI
BLOIO-GY
LKIH-GFD
MNMNBV-C
WERT-YIO
5. A male J marries a female L with MERRF disease. All their children have the disease. Now one of J and L’s
son who has the disease marries a woman who doesn’t have the disease. None of their children has the disease.
However, when the daughter of J and L who has the disease marries a man who doesn’t have the disease, all
their children have the disease. Explain how the disease is inherited.
6. T or F: If a flower is pink but its parents were red and white, it is an example of pleiotropy.
7. Compare and contrast pleiotropy and polygenic inheritance. ____________________
_____________________________________________________________________
8. Sickle cell disease is an example of _______________________________________.
9. Sutton’s Chromosome Theory of Heredity proposed that _______________________
____________________________________________________________________.
10. Morgan did many tests on flies. He discovered wild type and mutant phenotypes. Define those.
_________________________________________________________ What is a “vestigial” trait?
_______________________________________________
11. Since the mutant phenotype was found only in males, Morgan discovered _________
__________________________, which (supported/shot down) the theory of heredity.
12. What are “sex-linked” genes? How do they cause certain disorders? ______________
_____________________________________________________________________
13. What are linked genes? Do they follow Mendel’s Law of Independent Assortment?
_____________________________________________________________________
14. A dog that is heterozygous for two traits (i.e. BbHh) mated with a dog with recessive genes (bbhh). The
majority of the puppies had the phenotypes of their parents. What does this suggest about the two traits?
______________________________________
15. Those puppies that didn’t have either parent’s phenotype are called ___________________ offspring.
16. The probability of recombination depends on ________________________________ and is higher
when ____________________________________________________.
17. What is genomic imprinting? _____________________________________________
18. Why does tortoiseshell cat have pattern of different colors?