PS3+F11+Key - J. L. Marsh Fall 2011 Due 10/11/11 Bio D137...

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Unformatted text preview: J. L. Marsh Fall 2011 Due 10/11/11 Bio D137 Human and Eukaryotic Genetics Problem Set #3 (b) Repeat the above meiotic diagrams for the couple's next child who is a colorblind daughter with Turner syndrome. Sex det & disjunction 1. Green-shifted colorblindness is sex-linked recessive. A green-shifted colorblind woman and a man with normal vision have a colorblind son with Klinefelter's syndrome. (a) Does the son's vision phenotype tell us whether nondisjunction occurred in the father or in the mother? Diagram two different cases of meiosis in the egg and sperm and the union of the necessary gametes that could produce a colorblind Klinefelter's from this union.Be sure to label the appropriate chromosomes with the alleles for color vision. Answer: For the son to be colorblind, he must inherit both X c s from the mother (0.5 points) since this is recessive and a Y from the dad, so he is X c X c Y (0.5 points). So nondisjunction must have occurred during meiosis I (0.5 points) OR meiosis II (0.5 points) in the mother so that an X c X c egg is fertilized by a Y-bearing sperm (Diagram for normal meiosis in father (1point), diagram for non disjunction in meiosis I (1 point), diagram for non disjunction in meiosis II (1 point)) Answer: This daughter is X c O (0.5 points). Nondisjunction must have occurred in the father (0.5 points) during meiosis I (0.5 points) OR meiosis II (0.5 points) so that a sperm without any sex chromosome fertilizes an egg with an X c chromosome. (Diagram for normal meiosis in morther (1point), diagram for non disjunction in meiosis I (1 point), diagram for non disjunction in meiosis II (1 point)) Penetrance 09 2. Lobster claw syndrome, is a rare congenital deformity of the hand where the middle digit is missing, and the hand is cleft where the metacarpal of the finger should be. This split gives the hands the appearance of lobster claws. This (ectrodactyly) is an autosomal dominant disorder. Bree Walker, the news anchor had this disorder. The Vadoma tribe, living in the west of Zimbabwe on the Zambezi river valley, is somewhat reproductively isolated as they are surrounded by Bantu and have few contacts with the Bantu majority. A substantial majority of the Vadoma tribe has this condition (known as ectrodactyly) in which the middle three toes are absent and the two outer ones are turned in, resulting in the tribe being known as the "two toed" or "ostrich footed" tribe. Thebeing known as the "two toed" or "ostrich footed" tribe....
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This note was uploaded on 12/13/2011 for the course BIOSCI 137 taught by Professor Staff during the Fall '11 term at UC Irvine.

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PS3+F11+Key - J. L. Marsh Fall 2011 Due 10/11/11 Bio D137...

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