Describe a Barr Body
They are intact X chromosomes which are highly condensed and transciptionally repressed.
They are intact X chromosomes which are lightly condensed and transcriptionally repressed.
They are intact Y chromosomes which are highly condensed and transcriptionally repressed.
What is a condensed inactivated X chromosome?
X-linked
Y-linked
Barr Body
How can a female heterozygote phenotypically display a mosaic phenotype?
X-chromosome inactivation can phenotypically cause this for X- linked genes to display a mosaic phenotype.
X-chromosome inactivation can phenotypically cause this for X- linked genes to display a mosaic phenotype. This can also occur in males with a XXY genotype.
Y-chromosome inactivation can phenotypically cause this for Y- linked genes to display a mosaic phenotype.
Tortoiseshell cats are mostly...
Female
Male
Homozygous
Heterozygous
Both Female and Heterozygous
What's an example of random X-inactivation?
Tortoiseshell pattern
Down syndrome
Siamese cat
What is an example of a reversible epigenetic process?
Y-chromosome activation
X-chromosome inactivation
What does epigenetic mean?
Not a change in DNA sequence but a change in chromatin state.
A change in DNA sequence and a change in chromatin state.
Multiple gene sequences are cut out of the X-inactivation
X-inactivation is...
Erased during Mitosis, and the chromosome is passed onto the progeny in its original, active state.
Erased during Meiosis, and the chromosome is passed onto the progeny in an altered state.
Erased during Meiosis, and the chromosome is passed onto the progeny in its original, active state.
If extra X chromosomes are inactivated, why does XXY (Klinefelters) produce a clinical syndrome?
Up to 25% of some x-linked genes in humans escape inactivation. This includes the genes within the pseudoautosomal regions (PARs) of the Y chromosomes.
Up to 75% of some x-linked genes in humans escape inactivation. This includes the genes within the pseudoautosomal regions (PARs) of the X and Y chromosomes.
Up to 25% of some x-linked genes in humans escape inactivation. This includes the genes within the pseudoautosomal regions (PARs) of the X and Y chromosomes.
Few genes are shared by both X and Y because...?
Genes that are unique to the X chromosome are X-linked genes.
Genes that are unique to the Y chromosome are Y-linked genes.
Genes found on the sex chromosomes are sex-linked genes.
All are correct.
What type of traits exhibit sex-dependent inheritance patterns?
X-linked traits
Y-linked traits
Sex linked traits
The white gene in drosophila is...
X linked and is located on the x chromosome
Y linked and located on the Y chromosome
Sex independent
What would you call a diploid individual that carries only one copy of a given gene?
Hemizygous, Hemizygote
Heterozygous, Heterozygote
Homozygous, Homozygote
In XX/XY species, the XY sex is________ for X-linked genes.
Hemizygous
How would you denote a Wild type white allele?
w-
w+
w
Hemizygosity is phenotypically equivalent to...?
Sex linked
Heterozygosity
Homozygosity
X & Y act as a homologous pair during what?
Mitosis and daughter cell formation
Meiosis and gamete formation
Meiosis II and gamete formation
What is a unique aspect(s) of X-linked inheritance?
XY male parents normally cannot pass their X chromosome to male progeny
A male needs to receive only 1 recessive allele to display the recessive phenotype, but females need to receive 2 recessive alleles.
A heterozygous female for an X-linked trait can produce sons who display the recessive phenotype, regardless of her mate's X-chromosome genotype.
X-linked traits often deviate from Mendelian ratios
What is true about X-linked recessive conditions?
It effects females more often than males.
It effects males more often than females.
It equally effects males and females both.
