The genetic basis of population divergence leading to adaptive radiation and speciation is a major unresolved problem of evolutionary biology. Molecular elucidation of "speciation genes" advanced recently, yet it remains without clear identification of the gene complexes participating in reproductive isolation between natural populations, particularly, in sympatry. Genetic divergence was discovered between Drosophila melanogaster populations inhabiting ecologically contrasting, opposite slopes in "Evolution Canyon" (EC), Mt. Carmel, Israel. Interslope migration of flies is easy and verified. Nevertheless, significant interslope D. melanogaster population divergence was established at EC involving habitat choice, mate choice, thermal and drought tolerances, adaptive genes, and mobile elements. Parallel patterns of stress tolerance, habitat choice, and mate choice were demonstrated in Drosophila simulans at EC, although on a smaller scale. However, some tests for interslope genetic differentiation in Drosophila, derived from the opposite EC slopes, gave somewhat controversial results. Here we present new empirical data on interslope genetic divergence of Drosophila at EC, and summarize previous supporting and controversial results. We suggest that Drosophila populations at EC represent a rare example, demonstrating how selection overrides migration, and propose an ad hoc ecological model of incipient sympatric divergence.
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http://dx.doi.org/10.1073/pnas.0608777103 | DOI Listing |
Proc Natl Acad Sci U S A
November 2023
Departamento de Agricultura y Medio Ambiente, Escuela Politecnica Superior de Huesca, Universidad de Zaragoza, Huesca 22071, Spain.
Ecological divergence without geographic isolation, as an early speciation process that may lead finally to reproductive isolation through natural selection, remains a captivating topic in evolutionary biology. However, the pattern of genetic divergence underlying this process across the genome may vary between species and mating systems. Here, we present evidence that an annual and highly selfing grass model species, has undergone sympatric ecological divergence without geographic isolation.
View Article and Find Full Text PDFSci Data
August 2023
Research Center of Crop Stresses Resistance Technologies, Yangtze University, Jingzhou, 434025, China.
Wild barley, from "Evolution Canyon (EC)" in Mount Carmel, Israel, are ideal models for cereal chromosome evolution studies. Here, the wild barley EC_S1 is from the south slope with higher daily temperatures and drought, while EC_N1 is from the north slope with a cooler climate and higher relative humidity, which results in a differentiated selection due to contrasting environments. We assembled a 5.
View Article and Find Full Text PDFThe theories of sympatric speciation (SS) and coding and noncoding (cd and ncd =repeatome) genome function are still contentious. Studies on SS in our two new models, "Evolution Canyon" and "Evolution Plateau", in Israel, divergent microclimatically and geologically-edaphically, respectively, indicated that in ecologically divergent microsites SS is a common speciation model across life from bacteria to mammals. Genomically, the intergenic ncd repeatome was and is still regarded by many biologists as "selfish," "junk," and non-functional.
View Article and Find Full Text PDFNew Phytol
January 2023
School of Science, Western Sydney University, Penrith, NSW, 2751, Australia.
The considerable drought tolerance of wild cereal crop progenitors has diminished during domestication in the pursuit of higher productivity. Regaining this trait in cereal crops is essential for global food security but requires novel genetic insight. Here, we assessed the molecular evidence for natural variation of drought tolerance in wild barley (Hordeum spontaneum), wild emmer wheat (Triticum dicoccoides), and Brachypodium species collected from dry and moist habitats at Evolution Canyon, Israel (ECI).
View Article and Find Full Text PDFPlant Biotechnol J
January 2023
Western Crop Genetics Alliance, Future Food Institute, Western Australian State Agricultural Biotechnology Centre, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia.
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