ANT203Y1 Lecture Notes - Lecture 7: Down Syndrome, Patau Syndrome, Allosome
Document Summary
Lecture 7: the modern study of human genetics. Trisomy 21: facial features that ar distinct for this syndrome: survival rate is high (age of mother imp) Trisomy 13 and 18 are far more severe (dont survive as long) Xy can be either a female phenotype or an xx male phenotypes (some rare cases) What leads to this pattern emerging? (happens during recombination: crossing over) Xy female: either the sry region is not acting up, its not on the y anymore, could be due to segregation during meiosis. Dont have determining factors to turn into male, even with the presence of y chromosome. Xxy: either the egg or the sperm had incomplete segregation, one of the gametes had two chromosomes, may have had a sperm with xy or egg with xx. X: either egg or sperm didn"t have a second chromosome.
