(genetics) Inheritance for genes on the Y chromosome
Sex chromosomes are not only relevant for sex determination. They carry genes that are associated with other traits. Thus, it is not uncommon to see certain traits manifesting as sex-linked. In humans and other animals, there are two types of sex-linked inheritance: (1) X-linked inheritance and (2) Y-linked inheritance.
Y-linked inheritance is a form of inheritance for the genes located on the Y chromosome. In human and other mammalian males, the sex chromosomes are the X and Y chromosome. Y chromosome is smaller than the X chromosome and thus, carries relatively fewer genes. Apart from the genes for sperm development, appropriate hormonal output, and other traits characterizing males, the Y chromosome also carries genes other than for sex determination.
Hypertrichosis of the ears, webbed toes, and porcupine man are examples of Y-linked inheritance in humans. Hypertrichosis of the ears (or hairy ears) is a condition wherein there is a conspicuous growth of hair on the outside rim of the ear. Webbed toes condition is characterized by having web-like connection between second and third toes. Porcupine man is a condition when the skin thickens and gradually becomes darker, scaly, rough, and with bristle-like outgrowths. Since Y-linked inheritance involves the Y chromosome, Y-linked inheritance is passed on from father to son.
- Holandric inheritance