background: cytogenetic analysis, y-chromosome microdeletion screening, fish techniques and other genetic methods have helped in finding the causes of infertility in azoospermic or severe oligoazoospermic cases in the last decade. objective: in the present study, we characterized an abnormal y-chromosome, detected as a mosaic in an azoospermic male ascertained for infertility. materials and met...

Recombination shapes nucleotide variation within genomes. Patterns are thought to arise from the local recombination landscape, influencing the degree to which neutral variation experiences hitchhiking with selected variation. This study examines DNA polymorphism along Chromosome 4 (element B) of Drosophila americana to identify effects of hitchhiking arising as a consequence of Y-linked transm...

Unlike the autosomes, recombination between the X chromosome and the Y chromosome is often thought to be constrained to two small pseudoautosomal regions (PARs) at the tips of each sex chromosome. PAR1 spans the first 2.7 Mb of the proximal arm of the human sex chromosomes, whereas the much smaller PAR2 encompasses the distal 320 kb of the long arm of each sex chromosome. In addition to PAR1 an...

Y chromosome variation is determined by several confounding factors including mutation rate, effective population size, demography, and selection. Disentangling these factors is essential to better understand the evolutionary properties of the Y chromosome. We analyzed genetic variation on the Y chromosome, X chromosome, and mtDNA of the greater white-toothed shrew, a species with low variance ...

The paternally inherited Y chromosome has been widely used in population genetic studies to understand relationships among human populations. Our interpretation of Y chromosomal evidence about population history and genetics has rested on the assumption that all the Y chromosomal markers in the male-specific region (MSY) are selectively neutral. However, the very low diversity of Y chromosome h...

Background and Aims: Azoospermia factor (AZF) region of the Y-chromosome has several genes which are responsible for normal spermatogenesis. Microdeletions of these genes are associated with azoospermia and oligospermia. These microdeletions are too small to be detected by karyotyping. They can be easily identified using polymerase chain reaction. The aim of this study is to determine the frequ...

background: in most mammals, sex is determined at the beginning of gestation by the constitution of the sex chromosomes, xy in males and xx in females. case: here we report an interesting case characterized by ambiguous genitalia and ovotestis in a newborn carrying an apparently female karyotype (46 xx). array comparative genomic hybridization (array-cgh) revealed an unbalanced rearrangement re...

Background: Microdeletions of the long arm of the chromosome Y are the most common molecular genetic cause of severe infertility in men which affect three regions of AZFa, AZFb and AZFc (Azoospermia factor). These regions contain various genes involved in spermatogenesis. The effect of ethnicity on the patterns of Y chromosome microdeletions has not been extensively studied, particulary in Iran...

The sex chromosomes of the tropical crop papaya (Carica papaya) are evolutionarily young and consequently allow for the examination of evolutionary mechanisms that drive early sex chromosome divergence. We conducted a molecular population genetic analysis of four X/Y gene pairs from a collection of 45 wild papaya accessions. These population genetic analyses reveal striking differences in the p...