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Industrial Agricultural Environments
Published in Kezia Barker, Robert A. Francis, Routledge Handbook of Biosecurity and Invasive Species, 2021
Robert G. Wallace, Alex Liebman, David Weisberger, Tammi Jonas, Luke Bergmann, Richard Kock, Rodrick Wallace
Modern agriculture is proving to be a leader in the next mass extinction (Broswimmer, 2002; Dawson, 2016). Along with agriculture’s advance, primary natural habitat and non-human populations are contracting across locales at record rates (Foley et al., 2011; Valladares et al., 2012; Sinclair and Dobson, 2015; Ferreira et al., 2015; Wolf and Ripple, 2017). At the same time, agriculture is founding new ecologies in the place of the lost landscapes. Agricultural production and trade promote invasive species and alternate xenospecific relationships, permitting emergent pathogens, pests and other previously marginalised populations to disrupt long-term ecosystemic function (Crowl et al., 2008; Paini et al., 2016; Chapman et al., 2017; Wyckhuys et al., 2019). The crops and livestock in and of themselves represent the greatest of such introgression (Hoffman, 2010).
Mitochondrial DNAs and Phylogenetic Relationships
Published in S. K. Dutta, DNA Systematics, 2019
Microevolutionary processes are currently being investigated by the study of genetic diversity in the mitochondrial genome. In addition to its small size and relative ease of extraction and purification two particular properties of the mitochondrial genome have led to the adoption of mitochondrial DNA (mtDNA) variation in studies concerned with recent phylogenetic comparison. These are the maternal mode of inheritance, and the absence of recombination in sexually reproduced lineages. Theoretical studies representing an extension of neutral gene theory have also been rapid. Not only can an expectation of the rate of gene substitution be formulated for the mitochondrial genome, so too can comparative levels of nuclear and mitochondrial diversity found within populations and with respect to mating behavior, migration rates, and population subdivision. Consequently, measurements of mtDNA diversity are revealing details of evolutionary processes concerned with the recent geographical and ecological differentiation of species. These studies are also likely to be informative in an analysis of rates of gene introgression and convergent evolutionary phenomena.
Chloroplast DNA and Phylogenetic Relationships
Published in S. K. Dutta, DNA Systematics, 2019
One of the more unexpected results of the study by Palmer et al.19 concerns the phylogenetic placement of radish, Raphanus sativa. The radish chloroplast genome was found to be significantly more closely related (1.1% divergence) to that of the section two species than the latter are to section one (Figure 2A). Although radish is normally placed in a separate genus from Brassica, it should be remembered that certain crosses can still be effected between the two groups.40 This is evidence of not only a great deal of genetic similarity, but it also raises the possibility that cytoplasmic exchange has occurred through interspecific hybridization and introgression.
Gamma-rays and EMS induced resistance to mungbean yellow mosaic India virus in mungbean [Vigna radiata (L.) R. Wilczek] and its validation using linked molecular markers
Published in International Journal of Radiation Biology, 2022
Hirdayesh Anuragi, Rajesh Yadav, Ravika Sheoran
The association of YR4, CYR1, and CEDG180 markers with the gene controlling MYMIV resistance are very useful in mungbean as they not only facilitate the quick and artificial disease environment free identification of resistance but also accelerate the development of MYMIV resistant varieties. In addition, it saves money, time, and labor incurred in the resistant varietal development as well. However, few mutants have generated the amplicon of a resistant locus through one marker and amplicon of the susceptible locus through another marker e.g. the mutant line ‘M-26′ exhibited the PCR product of resistant locus when amplified by YR4 and CYR1 but also gave rise to amplicons of susceptibility locus when amplified by CEDG180 primer. This might be probably attributed to either moderate resistance behavior or relative contribution of ‘R genes’ in imparting the resistance or involvement of more than one quantitative trait loci in the expression of the resistance trait, however, this needs to be further investigated. Previously, different genes were reported in mungbean and urdbean conferring resistance to YMD (Laosatit et al. 2020; Mishra et al. 2020). As a matter of fact, many other DNA markers earlier reported to be linked with YMD resistance, also need to be validated in diverse genotypes, as they can speed up the introgression of YMD resistance in other genotypic backgrounds and assist in the quicker development of YMD resistance varieties without any need of laborious field screening.
The expanding Anopheles gambiae species complex
Published in Pathogens and Global Health, 2020
Both of these recent studies acknowledge that teasing apart the different evolutionary processes of past introgression, present gene flow and incomplete lineage sorting is still a major challenge for the An. gambiae species complex. We know that in the laboratory all studied An. gambiae s.l. species will cross-mate and produce viable eggs [see [3], and refs therein]. But what happens in nature is still unclear. Some species (An. melas, An. merus, An. quadriannulatus, An. amharicus and An. bwambae) do not overlap in their distributions, so will never meet and mate, and there are pre-mating barriers between other species (e.g. [4]). However, two species (An. gambiae and An. coluzzii) do hybridize frequently in the wild, and there is also some evidence from genetic markers of rare (<0.1%) wild hybrids between other sympatric species.
Searching for archaic contribution in Africa
Published in Annals of Human Biology, 2019
Cindy Santander, Francesco Montinaro, Cristian Capelli
We can consider recombination and mutations as the basis of understanding an expected length of an introgressed tract in relation to the time since the admixture event. Introgression is distinct from incomplete lineage sorting (ILS) in that it should leave behind longer tracts, as the former being more recent (Liang and Nielsen 2014). The difference in the size of the tracts should provide a way to tell whether a shared tract with an archaic hominin is in fact introgression or the genomic relic from an earlier common ancestral population.