Y linkage
Encyclopedia
In mammals, Y-linkage refers to when a phenotypic trait is determined by an allele (or gene) on the Y chromosome
. It is also known as holandric inheritance.
The Y-chromosome is small and does not contain many genes, therefore few traits are Y-linked, and Y-linked diseases are rare. Because the only humans which have a Y chromosome are males, the genes are simply passed from father to son, with no interchromosomal genetic recombination
.
Chromosome Y deletions are a frequent genetic cause of male infertility
. Another example in humans of a y-linked trait was thought to be hairy ears (it may also be sex-limited).
However, this has been discredited.
Y chromosome
The Y chromosome is one of the two sex-determining chromosomes in most mammals, including humans. In mammals, it contains the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 60 million base pairs...
. It is also known as holandric inheritance.
The Y-chromosome is small and does not contain many genes, therefore few traits are Y-linked, and Y-linked diseases are rare. Because the only humans which have a Y chromosome are males, the genes are simply passed from father to son, with no interchromosomal genetic recombination
Genetic recombination
Genetic recombination is a process by which a molecule of nucleic acid is broken and then joined to a different one. Recombination can occur between similar molecules of DNA, as in homologous recombination, or dissimilar molecules, as in non-homologous end joining. Recombination is a common method...
.
Chromosome Y deletions are a frequent genetic cause of male infertility
Male infertility
Male infertility refers to the inability of a male to achieve a pregnancy in a fertile female. In humans it accounts for 40-50% of infertility. Male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity.-Pre-testicular...
. Another example in humans of a y-linked trait was thought to be hairy ears (it may also be sex-limited).
However, this has been discredited.