BIOL 201 Lecture Notes - Lecture 9: Sister Chromatids, Immature Ovum, Allosome
20 Feb 2018
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Document Summary
Haploid, half of them carrying x half of them carrying y: spermatids will develop into spermatozoa, the sex of the offspring is ultimately decided by which sex allele lies on the spermatozoa that fuses with the ovum. Meiosis is not perfect: it sometimes makes mistakes: the chromosomes duplicate, line up, but when in anaphase they"re supposed to go each to an opposite end of the cell, they don"t. )nstead, the chromosomes go only to one side of the cell: nondisjunction. Don"t need to know these examples for course, just some general knowledge: Examples: xo (just one x and no allele on the corresponding chromosomes), turner syndrome, 1 in 2500 girls. Short, ovaries do not develop normally, infertility, high risk of developing other abnormalities: xxy: klinefelter syndrome, 1 in 500 boys. Weak, language difficulties, tall, skinny, little facial hair, broad hips, infertile, some breast development among others: xxx: triple x syndrome, 1 in 1000 girls.
