noun, plural: Y linkages
(genetics) A form of sex linkage involving particularly the Y chromosome
Sex linkage is the phenotypic expression of a gene occurring in the sex chromosome. The manifestation of certain traits is due to the expression of the genes located in the sex chromosome.
In humans and other mammals, the sex chromosomes are the X chromosome and the Y chromosome. Females would have two X chromosomes and males have one X chromosome and one Y chromosome. As such, sex linkage may be classified as X linkage or Y linkage. X linkage is a sex linkage involving the X chromosome whereas Y linkage is a sex linkage involving the Y chromosome. Since there are more genes in the X chromosome than in the Y chromosomes there are more X-linked traits than Y-linked.
Y linkage is the state of a genetic factor (gene) being borne on the Y chromosome. Since the Y chromosome does not fully take part in chiasma formation and recombination, it is not amenable to analysis by conventional linkage methods. Thus, little is known about its content. There is a gene for the h-Y antigen, and indirect arguments suggest that there is a principle that determines the formation of the testis and masculinization of the fetus but its localization, though narrowing the limits, remains elusive.
- X linkage