Question
Question: If a genetic disease is transferred from a phenotypically normal but carrier female to only some of ...
If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is
(a) Autosomal dominant
(b) Autosomal recessive
(c) Sex-linked dominant
(d) Sex-linked recessive
Solution
It implies that the gene causing the trait or the disorder is situated on the X chromosome. Males have 2 chromosomes, one is X, and the second is Y chromosomes and females have two X chromosomes. Genes on the X chromosome are often recessive or dominant. The male and female expression is not the same.
Complete answer:
The sex-linked recessive disease is those which can express only the chromosome that they're recessive, goes to the individual in recessive instead of dominant form.
Let’s take the example of the Hemophilia A
It is an X-linked recessive disease in which the blood doesn't coagulate due to lack of factor 8. This is thanks to the mutation in genes of the X chromosome called F8.
Additional information: X-linked recessive traits that aren't related to female body qualities are basically communicated inside the recognizable characteristics, or phenotype, of men. This is thanks to the very fact that men only have one X chromosome. Subsequently, genes thereon chromosome not coding for gender are usually expressed within the male phenotype albeit they're recessive since there are not any corresponding genes on the Y chromosome in most cases.
So the correct answer is ‘(d) Sex-linked recessive’.
Note: Females can get an X-linked recessive disorder, but this is very rare. An abnormal gene on the X chromosome from each parent would be needed since a female has two X chromosomes. Female carriers can have a traditional X chromosome that's abnormally inactivated. This is called "skewed X-inactivation." These females may have symptoms almost like those of males, or they'll have only mild symptoms.