Y chromosome haplogroups: a correlation with testicular dysgenesis syndrome?

Y chromosome haplogroups: a correlation with testicular dysgenesis syndrome?

McElreavey K, Quintana-Murci L.
Reproduction, Fertility and Populations, Institut Pasteur, Paris, France. kenmce@pasteur.fr

Testicular dysgenesis syndrome encompasses low sperm quality, hypospadias, cryptorchidism and testicular cancer. Epidemiological studies and genetic data from familial cases suggest that testicular dysgenesis syndrome has a common etiology. The Y chromosome is known to encode genes that are involved in germ cell development or maintenance. We have therefore investigated if different classes of Y chromosomes in the general population (Y chromosome haplogroups) are associated with aspects of the testicular dysgenesis syndrome. We defined the Y chromosome haplogroups in individuals from different European counties who presented with either (i) oligo- or azoospermia associated with a Y chromosome microdeletion, (ii) unexplained reduced sperm counts (<20 x 10(6)/ml) or (iii) testicular cancer. We failed to find Y chromosome haplotype associations with either microdeletion formation or testicular cancer. However, in a study of the Danish population, we found that a specific Y chromosome haplogroup (hg26) is significantly overrepresented in men with unexplained reduced sperm counts compared with a Danish control population. The factors encoded by genes on this class of Y chromosome may be particularly susceptible to environmental influences that cause testicular dysgenesis syndrome. Our current data highlight the need for further analyses of clinically well-defined patient groups from a wide range of ethnic and geographic origins.

Another study that suggests a Y chromosome prone to infertility.

2 responses to “Y chromosome haplogroups: a correlation with testicular dysgenesis syndrome?

  1. Hmmm…

    Can’t recall which modern nomenclature haplogroup does Hg26 relates to but considering that the major European clades were all in Hg1 (roughly R1b), 2 (rouhghly I) and 3 (roughly R1a), it’s obviously a very minor clade among Danes (haplpgroup E, J?).

    I must say I find it unlikely that a direct Y-DNA lineage association with very low sperm quality, more in such a minority clade. Such strict correlation should have rendered the lineage exinct long ago. I’d rather think that a fraction of that lineage has recently developed in Denmark (and ony there probably) the sperm complication.

  2. “I find it unlikely that a direct Y-DNA lineage association with very low sperm quality, more in such a minority clade. Such strict correlation should have rendered the lineage extinct long ago.

    True, however Peter Frost has argued northern Europe was where sexual selection was skewed away from competition between males. If so it would presumably reduce male fertility competition.

    “In some environments, women competed against other women for a limited number of available men.”
    When did Europeans become ‘white’?

    Where sexual selection was focused on women a poor sperm quality lineage could have survived. That it is found among the blonde white skinned Danes is consistent with the theory.

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