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• 1 2020-05-06T00:46:47+00:00 Olivia Durant 4 plain 2020-05-08T23:52:45+00:00

  
  Hybridization and Gene Flow Patterns in a Novel Contact Zone Between Two Species of Native California Sunflowers 

  Overview: Recent species movement has resulted in two species of sunflowers co-occurring within a landscape previously occupied by one species. As a result, there is potential for interbreeding. In this study, we use DNA sequencing to determine if interbreeding has occurred between these species and if this has resulted in movement of genes between them. 
  
  Abstract: When closely related species have overlapping ranges hybridization may occur, and successful survival and reproduction of the resulting hybrid propagules can result in the creation of a hybrid lineage or introgression. Encelia californica and Encelia farinosa are two species of sunflowers native to southern California. E. californica’s range is restricted to coastal regions of Southern California and Baja Mexico while E. farinosa occurs in more arid regions including the Southwest United States and Northern Mexico. Recent conservation efforts have led to individuals of E. farinosa being planted west of its natural range such that they co-occur with populations of E. californica, resulting in a novel contact zone. Individuals with morphological traits from both species (putative hybrids) have been observed within this contact zone. Previous studies have shown that Encelia hybrids are likely to be restricted to first-generation except for in areas of human disturbance, where the formation of hybrid lineages and backcrossing with parental species is thought to occur more frequently. In this study, we used a reduced-representation next generation sequencing approach to determine whether hybridization has occurred between E. californica and E. farinosa in this novel contact zone and whether there is evidence of gene flow between species. To address these questions, leaves of E. californica, E. farinosa, and of presumptive hybrids based on morphological traits were collected from five different locations in southern California. DNA was extracted from each sample using a modified CTAB protocol, quantified, and prepared for sequencing using restriction digests (PST1 and MSE) and sequenced on Illumina’s Hi-Seq platform. Following sequencing data was aligned and filtered. Genetic data confirms the presence of hybrids and suggests that gene flow has occurred between E. farinosa and E. californica. This demonstrates that in conservation efforts it is important to consider the potential for hybridization before moving species to areas that are outside of their current range. 
  
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