PS 35-170 - Genetic variation and differentiation among Coastal Red Cedar (Juniperus virginiana silicoicola) populations across its geographical range.

Background/Question/Methods

The Coastal Red Cedar (J. viginiana Var. silicicola) is found along the coast from North Carolina south to Florida and west to SE. Texas. Phenotypical, the Coastal Red Cedar (CRC) is similar to the Eastern Red Cedar, except for the smaller branches and cones. CRC is aggressively colonizing open areas close to their native range, which is very similar to encroachment patterns of Eastern Red Cedar populations. I will use this information to determine how much variation is within and between nine SRC populations among its current range. Moreover, I will determine the potential source for CRC populations expanding their range into central Florida.
I sampled nine different locations across the range. I sampled 15-20 individuals from each location to get a good representation for the what the DNA looks like for each population. From there, I extracted the DNA from the leaf tissue and diluted the samples to have approximately 10 to 15 ng/ul for the genetic analysis. I conducted a polymerase chain reaction (PCR) using 8 different primers and sent the samples to MC Lab (California) to measure the PCR product. I used GenALEx to determine the levels of genetic differentiation within and among CRC populations.

Results/Conclusions

My preliminary results using 154 CRC trees revealed 57 alleles in the eight loci that I examined. The number of alleles in each population ranged from 21 in P8 and P5 to 40 in P1. The average number of alleles per loci ranged from 2.6 in P8 to 5.0 in P7. Similarly, observed heterozygosity is high in all populations, but it was generally lower than the expected heterozygosity, indicating some level of inbreeding in all populations. Moreover, Wright’s F-coefficients also supports some inbreeding among trees included in most populations (Fis=0.212). Wright’s F-coefficients also show an intermediate level of differentiation among populations (Fst=0.09). I test if genetic differentiation among CRC populations can be explained by isolation by distance. Finally, I discuss the consequences of these findings for the possible encroaching behavior of this species in coastal and other novel habitats.