OBJECTIVE: To investigate the prevalence of Y chromosome polymorphisms in Chinese men and analyze their associations with male infertility and female adverse pregnancy outcomes.
METHODS: The clinical data of 32,055 Chinese men who underwent karyotype analysis from October 2014 to September 2019 were collected. Fisher\'s exact test, chi-square test, or Kruskal-Wallis test was used to analyze the effects of Y chromosome polymorphism on semen parameters, azoospermia factor (AZF) microdeletions, and female adverse pregnancy outcomes.
RESULTS: The incidence of Y chromosome polymorphic variants was 1.19% (381/32,055) in Chinese men. The incidence of non-obstructive azoospermia (NOA) was significantly higher in men with the Yqh- variant than that in men with normal karyotype and other Y chromosome polymorphic variants (p < 0.050). The incidence of AZF microdeletions was significantly different among the normal karyotype and different Y chromosome polymorphic variant groups (p < 0.001). The detection rate of AZF microdeletions was 28.92% (24/83) in the Yqh- group and 2.50% (3/120) in the Y ≤ 21 group. The AZFb + c region was the most common AZF microdeletion (78.57%, 22/28), followed by AZFc microdeletion (7.14%,2/28) in NOA patients with Yqh- variants. There was no significant difference in the distribution of female adverse pregnancy outcomes among the normal karyotype and different Y chromosome polymorphic variant groups (p = 0.528).
CONCLUSIONS: Patients with 46,XYqh- variant have a higher incidence of NOA and AZF microdeletions than patients with normal karyotype and other Y chromosome polymorphic variants. Y chromosome polymorphic variants do not affect female adverse pregnancy outcomes.

The Y chromosome is theorized to facilitate evolution of sexual dimorphism by accumulating sexually antagonistic loci, but empirical support is scarce. Due to the lack of recombination, Y chromosomes are prone to degenerative processes, which poses a constraint on their adaptive potential. Yet, in the seed beetle, Callosobruchus maculatus segregating Y linked variation affects male body size and thereby sexual size dimorphism (SSD). Here, we assemble C. maculatus sex chromosome sequences and identify molecular differences associated with Y-linked SSD variation. The assembled Y chromosome is largely euchromatic and contains over 400 genes, many of which are ampliconic with a mixed autosomal and X chromosome ancestry. Functional annotation suggests that the Y chromosome plays important roles in males beyond primary reproductive functions. Crucially, we find that, besides an autosomal copy of the gene target of rapamycin (TOR), males carry an additional TOR copy on the Y chromosome. TOR is a conserved regulator of growth across taxa, and our results suggest that a Y-linked TOR provides a male specific opportunity to alter body size. A comparison of Y haplotypes associated with male size difference uncovers a copy number variation for TOR, where the haplotype associated with decreased male size, and thereby increased sexual dimorphism, has two additional TOR copies. This suggests that sexual conflict over growth has been mitigated by autosome to Y translocation of TOR followed by gene duplications. Our results reveal that despite of suppressed recombination, the Y chromosome can harbor adaptive potential as a male-limited supergene.

The present study aims to explore the relationship between the Y chromosome polymorphisms (1qh+, inv(9), 9qh+, 16qh+, group D/G, Yqh- and Yqh+) and the risk of unexplained recurrent miscarriage (URM). A total of 507 couples with URM were recruited as case group and 465 healthy couples as control group. The Y chromosome polymorphisms of the male individuals were analysed with the G-banding technique, and the results of the chromosome G-banding analysis were determined using the International Naming Standards of Human Genetics (ISCN). Logistic regression analysis was used to analyse the risk factors for URM. The detection rate of Y chromosome polymorphisms in the case group (12.03%) was higher than that in the control group (2.15%). Y chromosome polymorphisms were detected at significantly higher rates in the case group than in the control group. Using the normal Y chromosomes in individuals of the case group as reference, the partners of their counterparts were more likely to experience miscarriage. The couples who were Y chromosome-polymorphism carriers had shorter gestational age, increased frequency of URM and longer average interval between pregnancies. The results of logistic regression analysis revealed that Y chromosome polymorphisms, shorter gestational age, a higher frequency of miscarriage and longer pregnancy interval were independent risk factors for URM. Y chromosome polymorphisms may be associated with the risk of URM and may play an important role in the development of URM.