Genetics- Linkage and Epistasis Flashcards
What are the sex chromosomes in females?
XX
What are the sex chromosomes in males?
XY
When is a characteristic said to be sex-linked?
When the allele that codes for it is located on a sex chromosome
How is the Y chromosome different to the X chromosome?
The Y chromosome is smaller and contains fewer genes
Why are men more likely to show recessive alleles carried on the X chromosome?
They only have one X chromosome so express the characteristic even if it’s recessive
What are examples of X-linked disorders?
Colour-blindness and haemophilia
What does autosome mean?
Any chromosome that isn’t a sex chromosome
Why are genes on the same autosome said to be linked?
They are on the same chromosome so they’ll stay together during the independent segregation of chromosomes
Why are genes more closely linked the closer together they are on the autosome?
Because this means that crossing over is less likely to split them up
What is epistasis?
The allele of one gene masks the expression of alleles of other genes
