Genetic variation of mangrove species Avicennia marina in Iran revealed by microsatellite markers

Mangroves play an essential role in ecosystem dynamics but are reported to be regressing as human pressure increases on coastal zones. In order to ensure conservation of mangroves, genetic diversity in remaining population must be explored. Since Avicennia marina is an environmentally susceptible species, such studies including examination of its genetic variation is done in a worldwide range. During the present study the level of genetic variation of mangrove trees (A. marina) in three coastlines of Bushehr province (Southwest regions of Iran) was examined using microsatellite markers. Three microsatellite loci which were applied in the last large-scale study, detected high levels of allelic diversity here (14 alleles in total), essential for an accurate estimation of population genetic parameters. The levels of heterozygosity detected for each population, over all loci, ranged from 0.451 to 0.667 with an average of 0.589, indicating relatively appropriate level of genetic variation. The expected heterozygosity was larger than the observed heterozygosity leading to positive inbreeding coefficients in all three populations. Highly significant departures from Hardy-Weinberg Equilibrium were detected in populations. Reduced level of genetic variation was found in the central population indicating strong genetic structure among the other populations with larger area and less exploitation.