Ch. 5 The Chromosomal Basis of Mendelism Flashcards
Exam 2
What further evidence supports the chromosomal theory?
Non-disjunction because it leads to the formation of a cell with an abnormal amount of genetic material.
_________________ of chromosome 21 leads to _________________ _________________
Non-disjunction
Down Syndrome
What chromosome are sex-linked traits usually carried on and are males or females more affected?
X-chromosome
Males are more affected because they only have one X.
Which syndrom results in the non-junction of X-chromosome leading to 45, X0
Turner Syndrome
Which syndrome results in the non-junction of the X-chromosome (47, XXY)
Klinfelter’s Syndrome
In utero, all babies have both the Mullerian _________________ duct & the Wolffian _________________ duct.
Paramesonephric
&
Mesonephric
If the ______________ hormone is not present @ 4 to 6 weeks the gender defaults to _____________
(AMH) Anti-Mullerian Hormone
Female
Define intersex conditions
a person is born with reproductive or sexual anatomy that doesn’t fit the boxes of “female” or “male.
Define dosage compensation
The process by which organisms equalize the expression of genes between members of different biological sexes.
Dosage compensation ____________ excessive expression of ______________ genes in Humans and other mammals.
prevents
X-linked
Define what a Barr Body is
the inactive X-chromosome in the somatic cells of mammalian females.”
Females have two X chromosomes. Since the somatic cells of females are not involved in sexual reproduction. Here one of the two X chromosomes is inactivated by lyonization.
Match chromosome number with syndrome
(45, X)
(47, XXY)
Klinefelter
Turner
Klinefelter- (47, XXY)
Turner (45, X)
What is X-inactivation and what does it explain?
in early development, one cell in development is randomly inactivated.
Dosage compensation
What is another name for X-inactivation?
Lyonization
What controls sex determination in Reptiles?
Temperature variation
