Why in x linked disease, females carrier while males get it?

Question

Why in x linked disease, females carrier while males get it?

Answer 1

Because females have 2 X chromosomes but males have only one. So, during reproduction males get the one X chromosome and that chromosome carries the disease. Does  that make sense?

Answer 2

Because the genetic mistake is on the one X chromosome.

Women have two X chromosomes, so there's one with the mistake and one healthy one. The product(s) of that gene that are made from the healthy chromosome usually make up for the messed up product(s) from the disease-carrier chromosome.

In order to get the full impact of the disease, women would need to have BOTH X chromosomes that have the disease, and that is very rare.

However, there is a 50% chance of the diseased chromosome being passed on to offspring.

Males have one X chromosome and one (much smaller) Y chromosome. The Y chromosome does not have most of the genes contained on the X, and therefore can't "make up" for the messed up products of the diseased gene. So men have the bad effect of the disease just from the one X.

As you can see, there is a 50% chance of a woman passing on the condition to her offspring, and if the offspring is male, there is 100% chance that he will show effects of it - while the mother may have zero symptoms.

Therefore, the women are generally only carriers.

Answer 3

                       IF

Disease carrying gene on X chromosome =x' = Bad gene on X

Normal X chromosome = X

Normal Y chromosome = Y

                        THEN

Male has genetic makeup x'Y         Female x'X

Male --> Bad gene gets expressed no matter what and disease occurs

Female-->  Effect of x' gets masked by good genes on other X so becomes carrier. SImple!

Answer 4

Males are more prone to X-linked diseases because they only have one X chromosome, therefore they only have one allele for each X-linked gene (hemizygous). If they happen to carry a recessive, disease causing allele on their X, then they will have the disease. Examples include hemophilia and colour blindness.

Females do get X-linked diseases, but usually they must have recessive alleles on both X chromosomes to manifest the phenotype.

It should be noted that mammals inactivate all X chromosomes except one. What this normally means is that females shut off one X chromosome per cell. This inactivation happens early in development and creates populations of cells that are expressing different X chromosomes. This can lead moasic expression of some X-linked diseases. For example there are cases of females being colour blind in one eye and having normal vision in the other.  

Answer 5

women have two x chromosomes and men don't they have an x and y which is why men tend to get more diseases then women.