X-Inactivation exam Flashcards
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X Inactivation
A process in female cells where one of the two X chromosomes is randomly inactivated.
Why do females not have double the expression of X-linked genes compared to males?
Because one of the X chromosomes in female cells is randomly inactivated.
Barr Body
The highly condensed inactive X chromosome found in female cells.
What is the result of X inactivation in terms of gene expression?
It results in equal expression of X-linked genes between males and females.
Calico Cats
An example of X inactivation, displaying color patches due to the inactivation of specific X chromosomes.
How does X inactivation affect allele expression in different cells?
It can result in a female expressing different alleles of an X-linked gene in different cells.
What happens to the inactive X chromosome in female cells?
It becomes a Barr body and is not expressed.
Why is understanding X inactivation important?
It is crucial for grasping genetic expression and inheritance patterns in sexually dimorphic species.
What determines the color patches in calico cats?
The random inactivation of X chromosomes carrying different fur color alleles.
How many X chromosomes do males and females have?
Males have one X and one Y chromosome, while females have two X chromosomes.
What is the scientific term for the inactive X chromosome?
Barr body.
What is the significance of the Barr body in female cells?
It indicates the inactivated X chromosome, ensuring balanced gene expression.
How does X inactivation contribute to genetic diversity?
By allowing different alleles to be expressed in different cells.
What is the role of X inactivation in embryonic development?
It occurs early in development to ensure balanced X-linked gene expression.
What happens to the X chromosome with the black fur allele in calico cats?
It is expressed in regions with black fur and inactivated in regions with orange fur.
What is the outcome of X inactivation in terms of fur color in calico cats?
Different fur color patches due to the expression of different alleles.
How does X inactivation ensure equal gene expression between sexes?
By inactivating one X chromosome in females, balancing the gene dosage with males.
What is the visual evidence of X inactivation in animals?
Color patches in calico cats.
How does X inactivation affect males?
It does not occur in males; they only have one X chromosome.
What is the result of inactivating one X chromosome in female cells?
It leads to the formation of a Barr body and balanced gene expression.
How does X inactivation relate to genetic expression?
It ensures that X-linked genes are expressed equally in both sexes.
What is the significance of the random nature of X inactivation?
It leads to diverse allele expression in different cells.
What happens to the X chromosome with the orange fur allele in calico cats?
It is expressed in regions with orange fur and inactivated in regions with black fur.
How does X inactivation affect inheritance patterns?
It influences the expression of X-linked genes, impacting traits and inheritance.
What is the key concept behind X inactivation?
Random inactivation of one X chromosome in female cells to balance gene expression.
What is the role of X inactivation in sexually dimorphic species?
It ensures balanced expression of X-linked genes between males and females.
How does X inactivation occur?
Randomly during early development in female cells.