G trisomy 21 small is well tolerated but

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Unformatted text preview: e.g., trisomy 21 (small) is well tolerated, but abnormalities still result. Trisomy 13 and 18 are the only other trisomies recorded to survive in utero 4 Trisomy 13 usually die shortly after. baby looks fairly normal - count toes though. all the organs are abnormal 5 Trisomy 18 isn’t the baby’s karyotype.. internal organs 6 Trisomy 21 7 in germ tissue. only looking at 21. all other chromosomes are working normally e.g. chromosome 21 didn’t separate, so all chromosomes are in one cell Fertilization 21 Trisomy Monosomy Normal (2n) 8 Trisomy Monosomy Aneuploidy Aneuploidy for the X chromosome Humans: XY male, XX female -must have at least one X for viability → gene dosage Gene dosage is the number of copies of a gene present in a cell -need dosage of one for most genes on X chromosome 9 Aneuploidy Aneuploidy for the X chromosome What about females? XX -...
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This document was uploaded on 02/25/2014.

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