Chromosome theory, mitosis, and meiosis - AndersenLab/Genetic-Analysis GitHub Wiki

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• ☿ - Virgin Female
• ⚥ - Hermaphrodite
• ♂ - Male
• ♀ - Female

• Non-disjunction is the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.

Consider the following cross between a red eyed (wild type) male and a white eyed female. On average, approximately 1/2000 offspring will be red eyed males (X^w+Y) and white eyed female (X^wX^w). How can this be?

Red eyed males and white eyed females can result from non-disjunction occurring in meiosis I. These are the crosses that will produce these results:

• X^null x X^w+ will produce red eyed males.
• X^wX^w x Y will produce white eyed females.

Non-disjunction occurring during meiosis II can also produce the unexpected red eyed males and white eyed females.

• X^null x X^w+ will produce red eyed males.
• X^wX^w x Y will produce white eyed females.

• Non-disjunction I and II Video - Explanatory video of non-disjunction during meiosis I and II.
• Developing the Chromosome Theory
• Mitosis and Meiosis Guide - Good guide detailing how to count chromosomes and chromatids.