Molecular phylogeny of mangroves. VI. Intraspecific genetic variation in mangrove species Excoecaria agallocha L. (Euphorbiaceae).
Genomic DNA from 84 individuals of Excoecaria agallocha from seven mangrove populations were analysed for random amplified polymorphic DNAs (RAPDs) using 16 random 10-mer primers. Polymorphism within populations varied from 20% to 31%. At the interpopulation level, 111/149 (74%) of RAPDs were polymorphic. Restriction fragment length polymorphism (RFLP) analysis of 21 individuals (3 individuals randomly selected from the 7 populations) using 30 probe-enzyme combinations revealed a high level of interpopulation polymorphism (62.2%) indicating interpopulation genetic divergence. The polymorphic RAPDs and RFLPs were pooled, and clustering was carried out based on mean similarity for individual populations. The dendrogram showed groupings of populations from the West and East Coasts of India into separate clusters, at 60% similarity level. Further, RAPD and RFLP analysis of male and female plants showed approximately the same level of variation in both sexes, and no sex-linked markers were found. These results demonstrate that considerable intrapopulation and interpopulation genetic variations exist in E. agallocha, and that lack of genetic variation is not the reason for the morphological uniformity observed across the range of the species.
Lakshmi
M
M
M.S. Swaminathan Research Foundation, Taramani, Chennai, India. MDSAAA51@giasmd01.vsnl.net.in
Parani
M
M
Ram
N
N
Parida
A
A
D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D014644:Genetic Variation; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D019105:Random Amplified Polymorphic DNA Technique; D013045:Species Specificity; D014197:Trees / Q000235:genetics*
D018744:DNA, Plant