sex-linked inheritance Flashcards
What chromosome carries genes for certain characteristics like hair on the inside of the ear?
The Y chromosome.
Which genetic disorders are sex-linked?
Colour blindness and haemophilia.
What causes colour blindness?
The absence of proteins that make up the red or green cones in the retina, causing difficulty distinguishing red and green.
What is haemophilia?
A disorder where blood cannot clot properly, leading to excessive bleeding.
Which chromosome carries the genes for colour blindness and haemophilia?
The X chromosome.
How does haemophilia affect males and females differently?
Males have a higher risk because they have only one X chromosome, while females need both X chromosomes to carry the recessive allele to be affected.
What does it mean if a woman is a carrier of a sex-linked disorder like colour blindness or haemophilia?
She has one X chromosome with the recessive allele but does not show the disorder; she can pass it on to her children.
What is the genotype for a normal female who is a carrier of haemophilia?
XHXh.
What is the genotype for a male with haemophilia?
XhY.
What genotype represents a colour-blind male?
XbY.
What is the genotype for a female with normal vision who is a carrier of colour blindness?
XBXb.
What genotype represents a normal female with no colour blindness?
XBXB.
