Although Mendel's first law predicts that crosses between XY (or XO) males and XX females should yield equal numbers of males and females, individuals in a wide variety of metazoans transmit their sex chromosomes unequally and produce broods with highly skewed sex ratios. Here, we report two modifications to the cellular programme of spermatogenesis, which, in combination, help to explain why males of the free-living nematode species Rhabditis sp. SB347 sire <5% male progeny. First, the spermatogenesis programme involves a modified meiosis in which chromatids of the unpaired X chromosome separate prematurely, in meiosis I. Second, during anaphase II, cellular components essential for sperm motility are partitioned almost exclusively to the X-bearing sperm. Our studies reveal a novel cellular mechanism for the differential transmission of X-bearing sperm and suggest Rhabditis sp. SB347 as a useful model for studying sex chromosome drive and the evolution of new mating systems.
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http://dx.doi.org/10.1038/ncomms1160 | DOI Listing |
J Pediatr Psychol
December 2024
Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at the University of California, Los Angeles (UCLA), Los Angeles, CA, United States.
Objective: Adolescents and young adults with chronic diseases face unique challenges during the college years and may consume alcohol and other substances to cope with stressors. This study aimed to assess the patterns of substance use and to determine psychosocial correlates of these behaviors among college youth with type 1 diabetes (T1D).
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Pak J Biol Sci
November 2024
<b>Background and Objective:</b> Betta fish is one of the most popular ornamental fish because of their attractive body shape, especially for males. The fish development usually results in a similar number of males and females or an even higher number of females. This study aimed to determine the effect of various concentrations of honey and the age of larvae on the sex ratio of Betta fish.
View Article and Find Full Text PDFAm J Ind Med
December 2024
Department of Environmental, Agricultural, and Occupational Health, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska, USA.
Background: Farm operators are at a high risk of developing skin cancer due to their occupational sun exposure. With the growing incidence of skin cancer, it is also important to evaluate other occupational risk factors. Farm operators confront numerous physical, chemical, and biological hazards in their work environment.
View Article and Find Full Text PDFTrans R Soc Trop Med Hyg
December 2024
Department of Health Policy and Vanderbilt Institute for Global Health, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
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Reprod Health
December 2024
Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Plot 51-59, Nakiwogo Road, Entebbe, Uganda.
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