Sex linkage refers to when a gene controlling a characteristic is located on a sex chromosome X or Y. X and Y chromosomes. As human females have two X chromosomes and therefore two alleles , they can be either homozygous or heterozygous. Human males have only one X chromosome and therefore only one allele and are hemizygous for X-linked traits.
Sex linkage - Wikipedia
Sex Linked Genes. A particularly important category of genetic linkage has to do with the X and Y sex chromosomes. These not only carry the genes that determine male and female traits but also those for some other characteristics as well. Genes that are carried by either sex chromosome are said to be sex linked. Men normally have an X and a Y combination of sex chromosomes, while women have two X's.
Definition noun, plural: sex-linked genes A gene located in the sex chromosome. Supplement In human s, the sex chromosome s are the X chromosome and Y chromosome. Hence, a sex-linked gene may occur in either of these sex chromosome s. Since the X chromosome is a rather large structure than the Y chromosome , the X chromosome carries more gene s, which may not be found in Y chromosome.
Sex linkage describes the sex-specific patterns of inheritance and presentation when a gene mutation allele is present on a sex chromosome allosome rather than a non-sex chromosome autosome. In humans, these are termed X-linked recessive , X-linked dominant and Y-linked. The inheritance and presentation of all three differ depending on the sex of both the parent and the child. This makes them characteristically different from autosomal dominance and recessiveness. There are many more X-linked conditions than Y-linked conditions, since humans have several times as many genes on the X chromosome than the Y chromosome.