BIO 325 - Fall 2007 - Sample questions - I exam

BIO 325 - Fall 2007 - Sample questions - I exam - GENETICS...

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GENETICS (BIO 325) FALL 2007 Sample questions (I exam) _______________________________________________________________________ _ 1. The allele c causes albinism in mice ( C causes mice to be black). If the cross C/c x c/c is made, and there are 10 progeny, what is the probability that all the progeny will be black? 2. A couple without an ancestral history of Tay-Sachs disease (an autosomal recessive) have two normal children and an infant affected with Tay-Sachs. The sister of the husband wants to marry the brother of the wife; in such a mating, what would be the probability of their first child having Tay-Sachs disease? 3. A human disease afflicted a family as shown in the following pedigree. What is the most likely mode of inheritance of this disease? 4. In moss, the genes A and B are expressed only in the gametophyte. A sporophyte of genotype A/a; B/b is allowed to produce gametophytes. 1
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(i) What proportion of the gametophytes will be A; B ? (ii) If fertilization is random, what proportion of sporophytes in the next generation will be A/a; B/b ? 5. Answer if the following statements are true or false: (a) Homologous chromosomes carry alleles for the same genes in the same relative positions. (b) Homologous chromosomes regularly exchange parts by crossing over at meiosis. (c) Homologous chromosomes physically pair at mitosis. (d) Homologous chromosomes are found in pairs but they do not physically pair in interphase in a diploid cell. (e) Homologous chromosomes duplicate before entering prophase of mitosis such that each chromosome has two chromatids. 6. The black and yellow pigments in the coats of cats are controlled by an X-linked pair of alleles. Females heterozygous for these alleles have areas of black and areas of yellow in their coat (called tortoise-shell , or calico if there are also patches of white hair). (i) A calico cat has a litter of eight kittens: 1 yellow male, 2 black males, 2 yellow females, and 3 calico females. Assuming there is a single father for the litter, what is his probable color? (ii)
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This note was uploaded on 02/17/2009 for the course BIO 325 taught by Professor Saxena during the Fall '08 term at University of Texas.

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BIO 325 - Fall 2007 - Sample questions - I exam - GENETICS...

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