Bio 180 Lecture 15:01

observed unusual patterns of inheritance reciprocal

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Unformatted text preview: (Drosophila melanogaster). - Observed unusual patterns of inheritance - reciprocal crosses did not give same results. Example: Eye color in fruit flies red-eyed female x white eyed male F1: all red-eyed white-eyed female x red-eyed male F1: all females red-eyes all males white eyes Sex Chromosomes - In mammals and some other groups: females: 2 X chromosomes (XX) males: 1 X & 1 Y chromosome (XY). - X larger, carries more genes. Pair not homologous. - Non-sex chromosomes = autosomes. Sex Chromosomes And Gamete Formation - Pair at meiosis I, segregate into different gametes. - All female’s eggs carry one X 1/2 sperm carry an X, and 1/2 carry a Y. Inheritance Of X-Linked Genes - Genes carried only on X, not on Y “X-Linked” * Females: 2 copies of gene (one from each parent) Males: 1 copy (from mother). - Use Punnet squares: female gametes - Xa male gametes - Y no allele So, can we ex...
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This note was uploaded on 02/24/2014 for the course BIOL 180 taught by Professor Freeman during the Winter '07 term at University of Washington.

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