BIOL 1011 Lecture Notes - Lecture 11: Advanced Maternal Age, Semen Analysis, Barr Body
1 Nov 2016
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Document Summary
Nondisjunction is the failure of chromosome pairs to separate properly during meiosis or mitosis. The result of this error is a cell with a imbalance of chromosomes. Synapsis occurs when 2 homologous chromosomes come together and line up side by side resulting in a tetrad. Trisomy of chromosome 21-having 3 copies of a particular chromosome instead of the usual 2. Mental impairment, and a variety of addition developmental defects. Can be detected before birth by amniocentesis. Risk of down syndrome increases dramatically in mothers over age 35. Also known as trisomy 13, is a chromosomal aberration, a disorder in which a patient has an additional chromosome 13 due to. Small eyes that may have a split in the iris. Inheritance of only 1 x chromosome rather than the normal 2, (written as xo, not. Chromosome number is 45 in every somatic cell (45, x0) Have extra fold of skin in neck. Xxy condition an example of trisomy of sex chromosomes.
