Abstract Detail

Population Genetics/Genomics

De la Rosa-Conroy, Leonardo [1], Arteaga, M.C. [1], Eguiarte, Luis [2], Gasca, Jaime [1], Bullock, Stephen  [1], Bello-Bedoy, Rafael [3].

High genetic variation and low differentiation across Yucca schidigera (Asparagaceae) populations in Baja California.

Studies on how genetic variation distributes across plant populations have revealed information about the evolutionary history of North American plant species.  We investigated genetic diversity and differentiation in Mojave yucca (Yucca schidigera), a long-lived perennial native of northwestern Mexico and southwestern US. We used seven nuclear microsatellite markers to examine neutral genetic variation in 240 individuals sampled from 13 Mojave yucca (Yucca schidigera) populations. Our study area extends across a southern section of the species’ geographic distribution, in Baja California. We used ecological niche modeling (ENM) to project suitable climatic habitat for this species during the LIG (~120 ka), LGM (~21.5 ka) and Mid Holocene (~6 ka) and investigated possible changes in suitable habitat conditions for this species. We detected high genetic variation across Y. schidigera populations (AR = 9.94 ± 0.38 SE; Hexp = 0.791 ± 0.011 SE). Genetic variation decreased significantly with latitude (allelic richness: R2=0.38, P =0.023; expected heterocigosity: R2=0.32, P =0.042). The ENMs showed a large increase in suitable habitat available for Y. schidigera during the LGM. Our results support that during the late Quaternary, favorable climatic conditions were widely available for this species in northwestern Baja California. High genetic variation across our sample suggests large historic effective population sizes for this section of the species distribution. We detected low, but significant genetic differentiation among populations (amova: FST =0.0678; P < 0.001) which was consistent with the slight geographic structure of the three genetic components detected by the Bayesian clustering algorithm. Geographic distance was significantly correlated with genetic differentiation among populations (r =0.38; P=0.004; partial Mantel test). In conclusion, Y. schidigera populations hold high levels of genetic variation and most of this variation is found within populations. Low genetic structuring and high genetic diversity could be the result of large historic population sizes and high rates of gene flow through seed and pollen dispersal.

1 - CICESE, Biología de la Conservación, Carr. Tijuana-Ensenada No. 3918, Ensenada, Baja California, 22860, Mexico
2 - UNAM, Departamento de Ecología Evolutiva, Instituto de Ecología, Ciudad Universitaria, Coyoacán, Ciudad de México, 04510, Mexico
3 - UABC, Facultad de Ciencias, Carr. Tijuana-Ensenada No.3917, Ensenada, Baja California, 22860, Mexico

Baja California
ecological niche modelling
North America
spatial genetic structure
genetic diversity

Presentation Type: Oral Paper
Abstract ID:324
Candidate for Awards:Margaret Menzel Award

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