Experimental assessment of gene flow between transgenic squash and a wild relative in the center of origin of cucurbits

Pea, one of the founder crops from the Near East, has two wild species: Pisum sativum subsp. elatius, with a wide distribution centered in the Mediterranean, and P. fulvum, which is restricted to Syria, Lebanon, Israel, Palestine and Jordan. Using genome wide analysis of 11,343 polymorphic single nucleotide polymorphisms (SNPs) on a set of wild P. elatius (134) and P. fulvum (20) and 74 domesticated accessions (64 P. sativum landraces and 10 P. abyssinicum), we demonstrated that domesticated P. sativum and the Ethiopian pea (P. abyssinicum) were derived from different P. elatius genepools. Therefore, pea has at least two domestication events. The analysis does not support a hybrid origin of P. abyssinicum, which was likely introduced into Ethiopia and Yemen followed by eco-geographic adaptation. Both P. sativum and P. abyssinicum share traits that are typical of domestication, such as non-dormant seeds. Non-dormant seeds were also found in several wild P. elatius accessions which could be the result of crop to wild introgression or natural variation that may have been present during pea domestication. A sub-group of P. elatius overlaps with P. sativum landraces. This may be a consequence of bidirectional gene-flow or may suggest that this group of P. elatius is the closest extant wild relative of P. sativum.

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Little gene flow between domestic silkmoth Bombyx mori and its wild relative Bombyx mandarina in Japan, and possible artificial selection on the CAD gene of B. mori

Genes & Genetic Systems ◽

10.1266/ggs.87.331 ◽

2012 ◽

Vol 87 (5) ◽

pp. 331-340 ◽

Cited By ~ 3

Author(s):

Kenji Yukuhiro ◽

Hideki Sezutsu ◽

Toshiki Tamura ◽

Eiichi Kosegawa ◽

Kazuya Iwata ◽

...

Keyword(s):

Gene Flow ◽

Bombyx Mori ◽

Artificial Selection ◽

Wild Relative ◽

Bombyx Mandarina ◽

Cad Gene

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Recent and Historical Gene Flow in Cultivars, Landraces, and a Wild Taxon of Cucurbita pepo in Mexico

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.656051 ◽

2021 ◽

Vol 9 ◽

Author(s):

Carmina Martínez-González ◽

Gabriela Castellanos-Morales ◽

Josué Barrera-Redondo ◽

Guillermo Sánchez-de la Vega ◽

Helena S. Hernández-Rosales ◽

...

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Evolutionary Biology ◽

Management Practices ◽

Incomplete Lineage Sorting ◽

Genetic Material ◽

Genotyping By Sequencing ◽

Wild Relative ◽

Lineage Sorting ◽

Evolutionary Trajectory

Gene flow among crops and their wild relatives is an active study area in evolutionary biology and horticulture, because genetic exchange between them may impact their evolutionary trajectories and increase the genetic variation of the cultivated lineages. Mexico is a center of diversity for the genus Cucurbita that includes pumpkins, squash and gourds. Gene flow between domesticated and wild species has been reported as common in Cucurbita; but gene flow among populations of C. pepo ssp. pepo from Mexico and its wild relative has not been studied. We used 2,061 SNPs, derived from tunable genotyping by sequencing (tGBS) to estimate gene flow among 14 Mexican traditional landraces of C. pepo ssp. pepo, also including individuals from five improved cultivars of C. pepo ssp. pepo and C. pepo ssp. ovifera var. ovifera, and individuals of their wild relative C. pepo ssp. fraterna. We found moderate to high levels of genetic diversity, and low to moderate genetic differentiation. In the test of introgression between lineages, we found that all possible arrangements for ancestral and derived sites between the lineages showed similar frequencies; thus, incomplete lineage sorting, but also gene flow, might be taking place in C. pepo. Overall, our results suggest that gene flow between these subspecies and cultigens, incomplete lineage sorting and the retention of ancestral characters shaped the evolutionary trajectory of C. pepo in its area of origin and diversification. In addition, we found evidence of the use of Mexican landraces as genetic material for the improvement of commercial cultivars. The landraces of Mexico are an important source of genetic diversity for C. pepo, which has been preserved both by management practices of small farmers and by the natural gene flow that exists between the different crop fields of the region.

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Eco-Geography of Feral Cotton: A Missing Piece in the Puzzle of Gene Flow Dynamics Among Members of Gossypium hirsutum Primary Gene Pool

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.653271 ◽

2021 ◽

Vol 9 ◽

Author(s):

Valeria Alavez ◽

Ángela P. Cuervo-Robayo ◽

Enrique Martínez-Meyer ◽

Ana Wegier

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Gossypium Hirsutum ◽

Gene Pool ◽

Ecological Niche Modeling ◽

Natural Fiber ◽

Center Of Origin ◽

Genetic Diversity And Structure ◽

Primary Gene Pool ◽

Primary Gene

Mexico is the center of origin and genetic diversity of upland cotton (Gossypium hirsutum L.), the most important source of natural fiber in the world. Currently, wild and domesticated populations (including genetically modified [GM] varieties) occur in this country and gene flow among them has shaped the species’ genetic diversity and structure, setting a complex and challenging scenario for its conservation. Moreover, recent gene flow from GM cultivars to wild Mexican cotton populations has been reported since 2011. In situ conservation of G. hirsutum requires knowledge about the extent of its geographic distribution, both wild and domesticated, as well as the possible routes and mechanisms that contribute to gene flow between the members of the species wild-to-domesticated continuum (i.e., the primary gene pool). However, little is known about the distribution of feral populations that could facilitate gene flow by acting as bridges. In this study, we analyzed the potential distribution of feral cotton based on an ecological niche modeling approach and discussed its implications in the light of the distribution of wild and domesticated cotton. Then, we examined the processes that could be leading to the escape of seeds from the cultivated fields. Our results indicate that the climatic suitability of feral plants in the environmental and geographic space is broad and overlaps with areas of wild cotton habitat and crop fields, suggesting a region that could bridge cultivated cotton and its wild relatives by allowing gene flow between them. This study provides information for management efforts focused on the conservation of wild populations, native landraces, and non-GM domesticated cotton at its center of origin and genetic diversity.

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