Sex linked traits are carried on what chromosome?

Answer 1

The X chromosome is linked to the overwhelming majority of sex linked traits, except for one - gender.

Short Answer:

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 2

Usually the X chromasome as the Y chromasome is generally considered to be a dud.

Answer 3

Original answer: "any of the autosomes"

My answer from BIO quiz: "X chromosomes"

(I got this question correct and one of the choices was "autosomes")

Answer 4

The sex chromosomes are the last (23rd) pair of chromosomes: Two X chromosomes in females, and one X and one Y in males.

Answer 5

In animals with XY sex chromosomes the allele for the trait is on the X chromosome.

Answer 6

The genes for sex-linked traits can be found on either the X or Y chromosome. They are most commonly found on the X chromosome.