Biology2

1. Which of the following human genetic disorders is sex linked? 

2. The sex chromosomes of a human female are ____. The sex chromosomes of a human male are ____. 

3. When looking at the inheritance of a single characteristic, Mendel found that a cross between two true-breeding peas (between purple and white, for example) always yielded a ______ in the F2 generation. 

4. Mendel made some crosses where he looked at two characteristics at once-round yellow peas crossed with wrinkled green peas, for example. He did this because he wanted to find out 

5.  When an individual has both IA and IB blood group alleles, both genes are expressed and the individual has group AB blood. This is an example of   

6. Most sex-linked traits in humans are carried on the ____ chromosome, and the recessive phenotypes are seen most often in ____.

7.

Assume that brown color is dominant over white color in mice. Suppose you wanted to know the genotype of a brown mouse. The easiest way to do it would be to:

8. Which of the following illustrates pleiotropy?

9. A fruit fly has two genes for eye color, but each of its sperm cells has only one. This illustrates 

10. Which of the following would be most useful for preventing a particular genetic disorder? 

11.

On a pedigree tracing the inheritance of PKU, a horizontal line joins a black square and a half-black circle. What fraction of this couple's children would you expect to suffer from PKU?

12.  In fruit flies, the allele for red eyes is dominant, and the allele for purple eyes is recessive. Normal gray body is dominant, and black body is recessive. A geneticist mated a heterozygous red-gray male with a purple-black female. She predicted that there would be four phenotypes of offspring in equal numbers, but she was wrong. Instead, 48% of the offspring were red-gray, 46% were purple-black, 3% were red-black, and 3% were purple-gray. She concluded that in the male, the red and gray genes were linked, and in the female the purple and black genes were linked. If this is the case, how would you account for the red-black and purple-gray offspring?