Biology 1001A Lecture Notes - Lecture 8: Fetus, Copy-Number Variation, Ploidy
25 Apr 2017
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Lectures 8- recombination in meiosis: the basic mechanism of dna recombination in meiosis. 2 differing dna molecules: mechanism for bringing dna close together, enzymes to cute, exchange, paste dna. Homologous chromosomes recombine during prophase of meiosis (maternal and paternal: evolutionary advantages of gene duplication. Creates variation: products of meiosis in animals vs. plants, fungi and algae. In plants: diploid organism (2n) goes through meiosis= spores (n). In fungi/ algae: gametophyte (n) produces gametes (n) by mitosis. In animals: goes through meiosis= haploid (n) gametes, fertilization into a zygote (2n): timing of meiosis in vertebrate life cycles, main differences between meiosis and mitosis. Sister chromatids separate during anaphase anaphase: characteristics of homologous chromosomes. Carry same genes, but diff alleles: reason why meiosis i is reductional and meiosis ii is equational Reductional: 2n down to n. meiosis i is to cut ploidy in half. Equational: ploidy (n) does not change in meiosis ii, but the c value drops.
