ANHB1101 Lecture Notes - Lecture 17: Molecular Anthropology, Ovulation, Exon
12 Jul 2018
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Meiosis resultant chromosomes from crossing over events> end result is that the daughter cells are not the same. Prophase 1> homologous chromosomes interact with each other> crossing over occurs here. Metaphase 1> spindle fibers attach to centromeres. First phase of meiosis you have haploid number. Telophase 2> 4 new cells> haploid number. 2nd meiotic division: spermatids (haploid) spermatid maturation into sperm cells (haploid) in epididymis (nourished by sertoli cells) Oogonia develop to primary oocytes by division and development. Only if fertilized completion of meiosis ii (casts off second polar body) non disjunction can occur during separation of chromosomes in 1 to 22 autosomals as well as sex cells 23 trisomy= 3 copies of the chromosome. Monosomy= 1 copy of chromosome karyoptypes: is chromosomes structure and number female is xx, male is xy numerical aberrations in autosomes. Often severe intellectual disability and physical abnormalities (eye, brain, circulatory defects, cleft palate) Rarely live more than a few months.
