Uploaded June 2015 | Updated September 2026, 2 weeks ago

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NOTE! The label for "sister chromatids" at 1:30 should say "homologous chromosomes"! Sadly, Youtube deleted the "annotations" feature that had previously corrected the error. Thanks for the viewers who noticed the problem!

Chromosomal problems can easily occur during reproduction. Continuing our discussion of reproduction, this screencast concerns common chromosomal abnormalities, specifically non-disjunction. During nondisjunction, an incorrect number of chromosomes are allocated into the resulting sex cells.