17.3 Flashcards
sickle cell anemia
first human disease shwon the be the result of a mutation in a protein
-caused by a defect in hemoglobin
nondisjunctuion changes chromosome number
nondisjunction: failure of homologues or sister chromatids to seperate properly during meioisis
leads to aneuploidy (gain or loss of a chromsome)
monosomy= chromsome loss
trisomy= chromosome gain
anueploid human embryouys rarely development
trisomy 21: down syndrome
may be a complete extra copy of chromosme 21
may be a translocation of key part of chromomsoe 21
mothers age infleunces risk
nondisjunction sex chromosomes
does not generally produce severe developmental abnormalities
may cause somewhat abnormal features, but many reach maturity