Friday, April 27, 2012

X-Linked Traits

X-linked traits are carried on the X chromosome. Since males have one X chromosome and one Y chromosome, they are more susceptible to X-linked diseases, such as hemophilia. There are other traits found on the X chromosome that are not diseases, such as pattern baldness. Since males only have one X chromosome they only need one copy of the gene to start early balding, females need two. Since this ratio is so skewed, there are much fewer females with X-linked diseases than males.


The picture above shows the inheritance of X-linked recessive traits in families. A father cannot pass on an X-linked disease to a son, only a daughter. A daughter will only show the trait if she receives both affected alleles from both parents. A only has to receive the affected allele from the mother to get the disease.

Some X-linked traits are hemophilia, color blindness, and pattern baldness. Do you know of any others?


Gossip_Grl said...

In biology class this was my favorite chapter! Several years ago I was going to breed my Chihuahua, I didn't but it was interesting getting another chance to go back and look at pedigrees and history of genes in the lines.

Hazel said...

Believe it or not, I was actually researching hemphiliacs yesterday so I actually knew what you were talking about today lol!

loverofwords said...

My son has red hair, which skipped several generations. Two of his five cousins on his father's side had red hair. When he was little, he thought he was adopted :(