The parental origin of the additional sex chromosomes in 8 cases with high-order sex chromosome polysomies was determined using DNA polymorphisms. The additional sex chromosomes were paternally derived in 3 48,XXYY cases, and maternal in origin in 1 48,XXXY case and 4 49,XXXXY cases. Thus, all extra chromosomes, within a particular patient, were always derived from only one parent. Their most likely origin was successive nondisjunction at the first and second meiotic division in one germ cell. The mechanism involved remains unclear, but appears to be independent of parental ages.
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http://dx.doi.org/10.1159/000154066 | DOI Listing |
Nat Genet
January 2025
Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA.
Segmental duplications (SDs) contribute significantly to human disease, evolution and diversity but have been difficult to resolve at the sequence level. We present a population genetics survey of SDs by analyzing 170 human genome assemblies (from 85 samples representing 38 Africans and 47 non-Africans) in which the majority of autosomal SDs are fully resolved using long-read sequence assembly. Excluding the acrocentric short arms and sex chromosomes, we identify 173.
View Article and Find Full Text PDFNat Commun
January 2025
Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, MD, USA.
The sex chromosomes contain complex, important genes impacting medical phenotypes, but differ from the autosomes in their ploidy and large repetitive regions. To enable technology developers along with research and clinical laboratories to evaluate variant detection on male sex chromosomes X and Y, we create a small variant benchmark set with 111,725 variants for the Genome in a Bottle HG002 reference material. We develop an active evaluation approach to demonstrate the benchmark set reliably identifies errors in challenging genomic regions and across short and long read callsets.
View Article and Find Full Text PDFJ Neurosci
January 2025
Fujian Key Laboratory for Translational Research in Cancer and Neurodegenerative Diseases, Institute for Translational Medicine, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China, 350122.
The development of the nervous system is a complex process, with many challenging scientific questions yet to be resolved. Disruptions in brain development are strongly associated with neurodevelopmental disorders, such as intellectual disability and autism. While the genetic basis of autism is well established, the precise pathological mechanisms remain unclear.
View Article and Find Full Text PDFGigascience
January 2025
Centre for Evolutionary & Organismal Biology, Zhejiang University School of Medicine, Hangzhou 310058, China.
Background: A thorough analysis of genome evolution is fundamental for biodiversity understanding. The iconic monotremes (platypus and echidna) feature extraordinary biology. However, they also exhibit rearrangements in several chromosomes, especially in the sex chromosome chain.
View Article and Find Full Text PDFSci Data
January 2025
Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China.
The flat-headed loach (Oreonectes platycephalus) is a small fish inhabiting headwaters of hillstreams of southern China. Its local populations are characterized by low genetic diversity and exceptionally high differentiation, making it an ideal model for studying small population isolates' persistence and adaptive potential. However, the lack of Oreonectes reference genomes limits endeavours toward these ambitions.
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