Why can a man who has sex-linked disorder pass tge disorder to his daughters but not his sons?

Answer 1

The sex-linked traits you refer to are probably located on the X chromosome. Because all boys receive their Y chromosomes from their fathers (after all, the mother has no Y chromosome), they cannot also have received an X chromosome which might contain the sex-linked trait from their fathers.

Answer 2

the son cannot inherit the gene from his father because his father is already giving him the Y chromosome, which makes him a male. Many sex-related diseases today are found only on the X chromosome.

Answer 3

Males carry few sex-linked traits, but one, gender, is important.

Women carry most.

The sex-linked traits are mostly on the X chromosome. This needs more explanation, so read on.

Short Answer Why:

There are just over a thousand genes on the X chromosome and about 26 on the Y. Of the 26 on the Y, 9 relate to sperm and one (SRY) relates to male anatomy, the others involved in general tasks.

The fact that there are a hundred times more genes on the X chromosome means that traits related to the X, and variations in those traits, are far far more common.

Sex-linked traits are those that can only be passed along from the father and not the mother or from the mother and not the father.

Obviously, males do carry and pass on sex-linked traits, just not very many.

Gender can only be passed along from the father, along with genes related to sperm.

Females pass on to the male offspring a larger number of traits, (such as some color blindness and male pattern baldness) which have no counterpart in the Y chromosome.

More:

Males have an X and a Y chromosome and females have two X chromosomes.

Because the Y chromosome is smaller than the X with far fewer genes, there are genes carried only on the X and only gotten from the mother. That does not mean that all males have Y chromosomes that are the same.

Overwhelmingly though, the absence of the set of genes on the Y chromosome results in the corresponding genes on the X chromosome being expressed, in particular all of the X-linked disorders of a gene of an X chromosome in a male do not have a second X gene that can be expressed to compensate. Thus, there are a set of sex-linked traits that can only come from the mother.

(Color blindness and male pattern baldness are the two most discussed examples.)

A male offspring (son) has the same Y chromosome as the father and hence any traits influenced by that chromosome.

A female offspring (daughter) has the same X chromosome as the father and hence any traits influenced by that chromosome. A recessive gene on the X from the father will not usually be expressed in a daughter, but a dominant gene on the X from the father will be expressed in the daughter.

For a female to inherit a trait associated with an X-chromosome recessive gene, there must be two copies, one from each parent.

Aside:

The issue of gender-connected inherited traits has much more complexity than this simple discussion can address. For example, not all of the so-called male characteristics are carried on the male (Y) chromosome. The expression of genes on other chromosomes, from both the mother and father, is influenced by genes on the Y chromosome or simply by the absence of two X chromosomes. The reader should investigate further.

Caveat: This discussion applies to humans and other mammals with the XX/XY sex determination system. See related links.

Fun Fact: A woman discovered that the Y chromosome was male. While studying worms, in 1905, Nettie Stevens at Bryn Mawr College identified the Y chromosome as the determining factor in gender.

Answer 4

A female has a gentoype of X,X and a male has a genotype of X,Y.

A daughter has X,X and gets one X from her mother ( X,X) and the other X from her father (X.Y). The son has X,Y and gets his X from his mother and the Y from his father. Because it is an X linked trait, the father's X goes to the daughter and she inherits whatever he has on his X. Whatever the mother has on her X goes to the son.

The son cannot get the X or any of the X linked traits from the dad because in meiosis ( sex cell reproduction) the offspring ( daughter or son) must get one thing from each parent.

Since the son has to have a Y, and the father is the only one who can supply him with it, the mother has to give him the X.

Answer 5

Yes, 1/2 a daughter's sex linked traits come form the father and these traits were in turn passed down to the father from his mother, so the daughter inherits some of her paternal grandmothers traits.

However, with a son it is the paternal grandfathers traits that are inherited.

Answer 6

A man who has a sex-linked disorder can pass the disorder to his daughters but not to his sons because sex-linked disorders are carried on the X chromosome and females have 2 of these chromosomes, unlike men who have just 1.

Answer 7

A man with a sex-linked disorder carries the affected gene on his X chromosome. Since men inherit one X chromosome from their mother and one Y chromosome from their father, they pass the affected gene to all of their daughters because they inherit an X chromosome from their father. Sons, on the other hand, inherit their Y chromosome from their father and thus do not inherit the affected X chromosome.

Answer 8

Some traits are passed down only with the X chromosome. A man has one X chromosome and one Y chromosome. If he passes the X chromosome to his child, it is bound to come out a girl.

Answer 9

It is because the Y chromosome does not contain many of the genes present in X chromosome