CELLS

2-27-03
Chromosome Linkage Disorders
Dependent on each other. One broken chain link affects all.
Ex: Allele #3 usually crosses over alone. With a disorder, it takes #7 with it. Some genes tend to always cross over with another gene combination, though.

Ploidy [chromosome count] disorders
Monoploidy- missing one chromosome of a homologous pair
Triploidy- has an extra chromosome for a homologous pair (replicated chromosomes did not split)
Polyploidy- an excess of the whole chromosome count (extra sets)

Sex-linked
Turner Syndrome- Only on sex chromosome-X, so genotype is X_. Just enough estrogen to be female. Never truly grows into a woman. Infertility.
Klinefelter Syndrome- non-disjunction: failure of replicated chromosomes to separate. Starts out as genotype XXY, but eventually one X turns into a Barr Body and becomes XxY. Girly man. Still fertile male, but girly.
Down¡¦s Syndrome- XXXX (Extremely masculin...