Sex linked traits are found mostly on the X chromosome.?

Sex linked traits are found mostly on the X chromosome. The Y chromosome in males is mostly for male sex characteristics. Some traits found on the X chromosome are colorblindness, hemophilia and a form of Vitamin D resistant Rickets. Punnett squares can also be done using the sex xhromosomes. I want you to try and cross a male that has hemophilia with a female who is normal but is a carrier for hemophilia. If they have a boy what is the percentage that their child will have the disease? If they have a girl what is the percentage their child will have the disease? (Hint: a male always gives the Y chromosome to his son and his X chromosome to his daughter. The male determines the sex of the child!!!).

Sex linked traits are found mostly on the X chromosome.?
Assume hemophilia A, which is a gene on the X chromosome. Let the gene be H for normal and h for hemophilia. A male with the disease is hy, his wife is Hh. If they have a boy, his genotypes will be Hy or hy, so he has a 50/50 chance of being a hemophiliac. If they have a girl, she can be Hh or hh, so she also has a 50/50 chance of being a hemophiliac or being a carrier.
Reply:If haemophilia is carried on the X chromosome, then we write it like this ( where H is normal and h= haemophilia) XH or Xh, where the H/h is superscript.





Here are the possible options:


XHXH = normal female


XHXh = carrier female ( normal)


XhXh = affected female





XHY = normal male


Xhy = affected male





So you have an affected male XhY and a carrier female XhXh





-------XH-------------Xh


Xh---XHXh-----XhXh


Y-----XHY--------XhY





You will have 50% of females carriers and 50% affected and 50% of males normal and 50% affected.
Reply:Let's say..





Male, normal: XY


Male, hemophiliac: X'Y


Female, normal: XX


Female, carrier: X'X


Female, hemophiliac: X'X'





X'Y x X'X





Gametes__X'__Y





X'______X'X__X'Y





X______X'X__XY





Ratio: 1:1:1:1





"If they have a boy what is the percentage that their child will have the disease?"





There is a 50% chance the boy will have hemophilia (X'Y), and a 50% chance that the boy will be normal (XY).





"If they have a girl what is the percentage their child will have the disease?"





There is a 50% chance the girl will have hemophilia (X'X'), and a 50% chance that the girl will be a carrier of hemophilia (having no symptoms) (X'X).