Joint Genetic Analyses of Mitochondrial and Y-Chromosome Molecular Markers for a Population from Northwest China

The Relationship Between Chromosomal Polymorphism and Male Reproductive Abnormalities

This study aims to investigate the association between chromosomal polymorphisms and abnormalities in male reproductive health. Within the period from January 2018 to December 2022, a cohort of 10,827 males seeking fertility services at our reproductive center was selected for inclusion in this study. Peripheral blood chromosomal karyotype analysis was conducted for each participant to identify carriers of chromosomal polymorphisms, who were subsequently categorized into a polymorphism group. Additionally, a control group was constituted by randomly selecting 1,630 patients exhibiting normal chromosomal karyotypes. The study conducted statistical analyses to compare clinical outcomes between the two groups, focusing on infertility, history of spontaneous miscarriage in partners, anomalies in reproductive development, fetal abnormalities, and sperm quality metrics. (1) Among the cohort of 10,827 males, chromosomal polymorphisms were identified in 1,622 participants, yielding a detection rate of 14.98%. This rate is significantly elevated in comparison to the baseline prevalence of 1.77% observed in the general population. (2) The predominant variant among these polymorphisms was related to the Y chromosome, accounting for 1,082 cases (66.71% of the polymorphic findings), corresponding to a detection rate of 9.99%. This is markedly higher than the approximate 0.09% prevalence noted within a normative demographic. (3) Statistical analysis revealed significant disparities between the chromosomal polymorphism group and the control group in several clinical outcomes. Notably, the rates of spontaneous abortion (18.06% vs. 1.35%), fetal anomalies (1.97% vs. 0.25%), and poor sperm quality (41.74% vs. 7.18%) were markedly higher in the polymorphism group. Additionally, incidences of testicular dysgenesis (2.28% vs. 0.92%) and hypogonadism in partners (0.62% vs. 0.37%) also demonstrated significant differences, underscoring the potential reproductive implications of chromosomal polymorphisms. The study establishes a significant link between chromosomal polymorphisms and critical reproductive outcomes, including male infertility, spontaneous miscarriages in partners, fetal anomalies, and reduced sperm quality. These findings highlight the clinical relevance of chromosomal polymorphisms in reproductive health assessments and suggest the necessity for their consideration in the diagnostic and therapeutic strategies for male reproductive disorders.

Genetic Background of Kirgiz Ethnic Group From Northwest China Revealed by Mitochondrial DNA Control Region Sequences on Massively Parallel Sequencing

The mitochondrial DNA (mtDNA) has been used to trace population evolution and apply to forensic identification due to the characteristics including lack of recombination, higher copy number and matrilineal inheritance comparing with nuclear genome DNA. In this study, mtDNA control region sequences of 91 Kirgiz individuals from the Northwest region of China were sequenced to identify genetic polymorphisms and gain insight into the genetic background of the Kirgiz ethnic group. MtDNA control region sequences of Kirgiz individuals presented relatively high genetic polymorphisms. The 1,122 bp sequences of mtDNA control region could differ among unrelated Kirgiz individuals, which suggested the mtDNA control region sequences have a good maternal pedigree tracing capability among different Kirgiz individuals. The neutrality test, mismatch distribution, Bayesian phylogenetic inference, Bayesian skyline analysis, and the median network analyses showed that the Kirgiz group might occurred population expansion, and the expansion could be observed at about ∼53.41 kilo years ago (kya) when ancestries of modern humans began to thrive in Eurasia. The pairwise population comparisons, principal component analyses, and median network analyses were performed based on haplogroup frequencies or mtDNA control region sequences of 5,886 individuals from the Kirgiz group and the 48 reference populations all over the world. And the most homologous haplotypes were found between Kirgiz individuals and the East Asian individuals, which indicated that the Kirgiz group might have gene exchanges with the East Asian populations.