BIOL 1001 Lecture Notes - Lecture 13: Homologous Chromosome, Sister Chromatids, Allosome
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Biol 1001 - lecture 13 - genetics & meiosis. Random alignment of homologous chromosomes during meiosis i. Either the maternal or paternal member of a homologous pair can end up at either pole of a cell. Homologues can go up or down in the previous figures. The chromosomes in a gamete are a mix of chromosomes from the two parents. Our gametes almost always contain both maternal and paternal chromosomes. During transition between prophase i and metaphase i, microtubules from spindle poles attach to kinetochores of chromosomes. Initial contacts between microtubules and chromosomes are random. Extremely important: allows mixing of maternal and paternal alleles of genes during meiosis i. Maternal and paternal genes are passed onto offspring via meiosis. As a result of microtubule alignment, the number of possible combinations of chromosomes in a gamete is . 2^n, or 2^23, or 8. 5 million combinations. For a cell with 8 chromosomes or 4 pairs, the haploid number is 4.