Evaluating cpDNA sequence variation as a tool for studying

population genetic structure in /Pitcairnia angustifolia/ in Puerto Rico

Elvia Melendez-Ackerman1

Jason Rausher2

Paola A. Olaya A.3

1,2 y 3 Universidad de Puerto Rico, Recinto de Rio Piedras

Pitcairnia angustifolia is a large, perennial terrestrial bromeliad endemic to Puerto Rico. It occurs in large colonies ranging from 300 to 900 m above sea level, and is usually found on karst, serpentine, or volcanic soils of moist and wet forests.  Geographically separated populations of this species show morphological differentiation: for example, the El Verde population has smaller unbranched inflorescences and those of Rio Abajo have larger, branched inflorescences.  The pollination biology of P. angustifolia has suggested that there may also be population differentiation in the degree of inbreeding depression. However, nothing is known about the genetic variation within and between populations of this species.  In this study we seek to develop molecular markers to characterize genetic diversity, test whether there is significant genetic differentiation between populations, and provide insights into processes such as pollen and seed movement.  Here we report the results of sequencing of four chloroplast regions -- rpl32-trnL(UAG), psbD-trnT(GGU), trnQ-5'rps16 and psbJ-petA -- in individuals of two different populations of P. angustifolia.  PCR products were sequenced for a set of 13 individuals from Rio Abajo and 9 individuals from El Verde to characterize sequence diversity and identify useful variable regions.  Including all four regions, a total of ~5500 basepairs were sequenced per individual, and a total of 3 variable sites were encountered, including one substitution and two indels.  These results will be used as single nucleotide polymorphism (SNP) markers that can be screened for large numbers of individuals in each population to obtain a fine-scale estimation of chloroplast genome distribution in P. angustifolia.