Robertsonian translocations resulting in fusions between sex chromosomes and autosomes shape karyotype evolution by creating new sex chromosomes from autosomes. These translocations can also reverse sex chromosomes back into autosomes, which is especially intriguing given the dramatic differences between autosomes and sex chromosomes. To study the genomic events following a Y chromosome reversa...

Y chromosome microdeletions are the second genetic cause of male infertility. The incidence of Y chromosome microdeletions can vary considerably depending on several factors, including patient selection criteria, population composition, and diagnostic protocols. They are associated with spermatogenic failure and lead to azoospermia or oligozoospermia. The advance in assisted reproductive techno...

Spermatogenesis is an essential stage in human male gamete development, which is regulated by many Y chromosome specific genes. Most of these genes are centred in a specific region located on the long arm of the human Y chromosome known as the azoospermia factor region (AZF). Deletion events are common in Y chromosome because of its peculiar structural organization. Astonishingly, among the sev...

BACKGROUND Some genes identified in the AZF locus are expressed only in germinal cells; others are ubiquitous. AZF microdeletions seem to occur at the earliest stages of ontogenetic development, and one might therefore assume that Sertoli cells preserve some immature characteristics and that their immunophenotype may be modified by the existence of a molecular defect. MATERIALS AND METHODS Tw...

The human Y chromosome harbours genes that are essential for spermatogenesis. Most of these genes lie in the male-specific region (MSY) of Y chromosome. Microdeletions of AZF within the MSY have been reported in infertile men. Widely different frequencies of such deletions (0-55%) have been reported from different populations. TSPY is another gene located in the MSY region that plays a signific...

The human Y-chromosome does not recombine across its male-specific part and is therefore an excellent marker of human migrations. It also plays an important role in male fertility. However, its evolution is difficult to fully understand because of repetitive sequences, inverted repeats and the potentially large role of gene conversion. Here we perform an evolutionary analysis of 62 Y-chromosome...

Amplicons--large, nearly identical repeats in direct or inverted orientation--are abundant in the male-specific region of the human Y chromosome (MSY) and provide targets for intrachromosomal non-allelic homologous recombination (NAHR). Thus far, NAHR events resulting in deletions, duplications, inversions, or isodicentric chromosomes have been reported only for amplicon pairs located exclusive...

BACKGROUND It has been hypothesized that Y-q microdeletion can account for significant proportion of infertility in men. There are three nonoverlapping regions referred to as the "azoozpermia factors" AZFa, AZFb, and AZFc from proximal to distal part of Y-q. These have been defined as spermatogenesis loci, this region deletions have been shown to be involved in male azoospermic or severe oligoo...