Conservation Genetics of the Endemic Mexican Heliconia uxpanapensis in the Los Tuxtlas Tropical Rain Forest

Abstract

ABSTRACT Heliconia uxpanapensis (Heliconiaceae) is an outcrossing endemic herb that grows within continuous and fragmented areas of the tropical rain forest of southeastVeracru ´z (Mexico). The genetic diversity, population differentiation, and genetic structure of seven populations of the studied species were assessed using inter-simplesequence repeat) markers. Population differentiation was moderately high (F ST range: 0.18–0.22) and indirect estimates of gene flow were rather low(Nm=0.65–0.83). Analysis of molecular variance indicated that the populations explained 22.2 percent of the variation, while individuals within the populationsaccounted for 77.8 percent. The similar and high level of genetic diversity found within populations of the continuous and fragmented forest suggests that H. uxp-anapensis has not suffered yet the expected negative effect of fragmentation. Genetic structure analyses indicated the presence of fewer genetic clusters (K=4) thanpopulations (N=7). Three of the four fragmented forest populations were assigned each to one of the clusters found within the continuous forest, suggesting theabsence of a negative fragmentation effect on the amount and distribution of genetic variation. Given the significant genetic structure combined with high geneticdiversity and low levels of gene flow, theoretical simulations indicated that H. uxpanapensis might be highly susceptible to changes in the mating system, whichpromotes inbreeding within fragmented populations. Thus, future conservation efforts in this species should be directed to ensure that levels of gene flow amongpopulations are sufficient to prevent an increment in the magnitude of inbreeding within fragments.Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.Key words: fragmentation; F-statistics; ISSR.