In sexual species, speciation occurs through the accumulation of genetic barriers to gene flow. In Caenorhabditis briggsae, one such barrier impedes gene flow between temperate strains and the tropical AF16 strain. Up to 20% of F2 progeny derived from crosses of AF16 to strains from the temperate clade exhibit a delayed development phenotype. This phenotype, which results from dysgenic interactions between maternal- and zygyotic-effect loci, causes a ~21% decrease in the intrinsic growth rate. The maternal-effect requires contributions from both parental genotypes. The dysgenic maternal-effect allele appears to be fixed in the temperate clade of C. briggsae and appears to have arisen between 700 and 15,000 y ago. The dysgenic zygotic allele appears to be present only in AF16 and also may be of recent origin.
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http://dx.doi.org/10.4161/worm.23535 | DOI Listing |
bioRxiv
December 2024
Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat, 49, Leuven, Belgium.
Temperature profoundly impacts organismal physiology and ecological dynamics, particularly affecting ectothermic species and making them especially vulnerable to climate changes. Although complex physiological processes usually involve dozens of enzymes, empirically it is found that the rates of these processes often obey the Arrhenius equation, which was originally derived for single-enzyme-catalyzed reactions. Here we have examined the temperature scaling of the early embryonic cell cycle, with the goal of understanding why the Arrhenius equation approximately holds and why it breaks down at temperature extremes.
View Article and Find Full Text PDFGenetics
December 2024
Department of Molecular Biology, Rowan-Virtua School of Translational Biomedical Engineering and Sciences, Stratford, NJ 08084, USA.
Sexual characteristics and reproductive systems are dynamic traits in many taxa, but the developmental modifications that allow change and innovation are largely unknown. A leading model for this process is the evolution of self-fertile hermaphrodites from male/female ancestors. However, these studies require direct analysis of sex-determination in male/female species, as well as in the hermaphroditic species that are related to them.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China.
The establishment of reproductive barriers such as postzygotic ybrid ncompatibility (HI) remains the key to speciation. Gene duplication followed by differential functionalization has long been proposed as a major model underlying HI, but little supporting evidence exists. Here, we demonstrate that a newborn F-box gene, , of the nematode specifically inactivates an essential phosphoglucomutase encoded by in its sister species and their hybrids.
View Article and Find Full Text PDFMicroPubl Biol
September 2024
Department of Chemistry and Biochemistry, California State University, Fresno.
Hybrid offspring dysfunction in cytoplasmic-nuclear hybrids (cybrids) implies that one parent's mitochondrial genome is incompatible with the nuclear genome of the other parent. In , cybrids exhibit increased mitochondrial reactive oxygen species (ROS). In this study, we measured the specific activity of markers for mitochondrial abundance (citrate synthase) and antioxidant enzyme response (catalase) in four cybrid lines.
View Article and Find Full Text PDFVet Parasitol Reg Stud Reports
September 2024
Universidade Tiradentes - UNIT, Graduate Program in Health and the Environment, Av. Murilo Dantas, 300, Bairro Farolândia, 49032-490, Aracaju, SE, Brazil; Instituto de Tecnologia and Pesquisa - ITP, Laboratory of Infectious and Parasitic Diseases, Av. Murilo Dantas, 300, Prédio do ITP, Bairro Farolândia, 49032-490 Aracaju, SE, Brazil.
The giant African land snail Achatina fulica is known to be the intermediate host of a number of nematode species that are prejudicial to human and veterinary health, being also an agricultural and urban pest. The present study investigated the presence of nematodes in A. fulica and other terrestrial mollusks in 24 municipalities of Sergipe State, northeastern of Brazil, in the dry and rainy seasons.
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