Biology 2581B Lecture Notes - Lecture 9: Heterosis, Demethylase, Allosome
21 Mar 2020
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Rest of group can be either but can"t breed. If largest female dies: next largest (ie. breeding male) replaces it. Epigenetics: heritable changes that don"t involve alterations in. Acetylated histones unmethylated cytosines = gene on. Unacetylated histones methylated cytosines = gene off. Red-eared slider turtles use temperature-based epigenetics to determine sex. Dmrt1 gene: produces transcription factor that triggers male development. @ low temp: male development demethylated = gene on. @ high temp: female development methylated = gene off. Leptodactylus pentadactylus (frog): 6 x and 6 y. Undergo alternate meiosis that affects prophase i. Sex chromosomes form stable ring-shaped meiotic chain. Understanding why some species have more sex chromosmes can help in understaing why humans have so little. Sex genes start developement but hormones produced largely determine sex. Voles skewed toward female development b/c of exposure to estrogen-based pesticides. A transcription factor (induces transcription in downstream genes) Testes secrete: - testosterone male development. Mullerian-inhibiting substance degrade female reproductive ducts.
