Exam 1: Lecture 5 Flashcards
what is the gene that encodes protein TDS
SRY
during which stage we haploid
meiosis/gametes
during which stage are we diploid
fertilization/zygote
heterogametic mean
sex produces 2 different gamete types with 2 different sex chromosomes
T/F: most mammals have 2 sexual phenotypes: m and F
true
when is having 1 sexual phenotype advantageous?
when the environment is stable and no genetic variation is needed
what is the pairing region for in X and Y chromosomes
the X and Y chromosomes pair during meiosis bc small region of shared homology
A male with a recessive mutation on his X chromosome means what
No counterpart on the Y so not able to make working gene so any defective genes on his X they become pseudo dominant and will express (phenotypically)
Y carries no balancing genes so susceptible to defects
hermaphroditism
both sexes in same organism
monoecious
both m and f reproductive structures in the same organism
dioecious
either m or female reproductive structures but not both in 1 organism
XX-XO system:
dosage system. 1 X is the threshold to be a male
ZW-ZZ system:
females are heterogametic
why is the Y seen as a “flip switcher”
default is female but if get an Y, switch is made to male
the pseudoautosomal regions are located where on a chromosome
at the tips
