lecture 15 Flashcards
whats a Barr body
a condensed and inactive X chromosome.
why does X inactivation occur
to balance the expression of genes on the x chromosome between males and females.
what is aotopolyploidy
are formed of many genomes of the same species (possibly the same individual),
what is allopolyploidy
whereas allopolyploids contain multiple genomes from distinct taxa
what is aneuploidy
Aneuploidy is an abnormal number of chromosomes
what is polyploidy
a whole number of extra sets of chromosomes, 2n, 3n.
what is trisomy and monosomy
Trisomy= three chromosomes
Monosomy = one chromosome
what is down syndrome
3 copies of the 21st chromosome
what gametes result from anaphase 1 non disjunction
n+1, n+1,n-1 and n-1
what gametes result from anaphase 2 non-disjunction
n+1,n-1, n, n
what is klinefelter syndrome
is Klinefelter syndrome. Where the person is a biological male but they have female phenotypes as they have an extra X chromosome, these people are XXY.
what is turner syndrome
There is also Turner syndrome in which the person is a biological female and have under expressed phenotypes, as they are one X.
why do X chromosome defects not show a mosaic pattern in Whane
The gene products move around the body.
what causes familial Down syndrome
a translocated C14 and C21, combined with 2 other C21 in a zygote
cri du chat is caused by what?
deletion of part of a C5
