The human Y chromosome: the biological role of a “functional wasteland”

“Functional wasteland,” “Nonrecombining desert,” and
“Gene-poor chromosome” are only some examples of the different
definitions given to the Y chromosome in the last decade. In
comparison to the other chromosomes, the Y is poor in genes,
being more than 50% of its sequence composed of repeated
elements. Moreover, the Y genes are in continuous decay probably
due to the lack of recombination of this chromosome. But the
human Y chromosome, at the same time, plays a central role in
human biology. The presence or absence of this chromosome
determines gonadal sex. Thus, mammalian embryos with a Y
chromosome develop testes, while those without it develop ovaries
(Polani [1]). What is responsible for the male phenotype is
the testis-determining SRY gene (Sinclair [2]) which
remains the most distinguishing characteristic of this
chromosome. In addition to SRY, the presence of other genes with
important functions has been reported, including a region
associated to Turner estigmata, a gene related to the development
of gonadoblastoma and, most important, genes related to germ cell
development and maintenance and then, related with male fertility
(Lahn and Page [3]). This paper reviews the structure and
the biological functions of this peculiar chromosome.