GENETIC DIFFERENTIATION BETWEEN TWO POPULATIONS OF THE GASTROPODA DIODORA GIBBERULA (FAMILY: FISSURELLIDAE) COLLECTED FROM FIVE DIFFERENT SITES ALONG THE COAST OF EL-ANFUSHI, ALEXANDRIA, EGYPT BASED ON RAPD ANALYSIS

Morphological and morphometric variations between two populations of Diodora gibberula (Order Archaeogastropoda, Family Fissurellidae) were investigated to verify whether these differences are supported by genetic differences. Samples of D. gibberula were collected from 5 sites along 3-km stretch of the tidal region of El-Anfushi, Alexandria Coast, Egypt. Discriminate analysis based on shell morphometries showed significant differences only in shell height and length of costae. No differences in cephalic or pallial tentacles were detected between the two populations, while the colours of shell and underside foot were distinctly separating them. Random amplified polymorphic DNA (RAPD) technique was used to assess the level of genetic variation in the two examined populations. Three arbitrary primers, when used individually in the polymerase chain reaction (PCR), amplified an average of 7 to 13 RAPD fragments ranging in size from 89 to 972 base pair (bp). Different molecular fingerprint patterns were obtained and the number of polymorphic bands was scored to calculate band-sharing ratio within populations. The present data reveals a high concordance between morphological and genetic differentiation between D. gibberula populations with the latter being much remarkable by RAPD analysis, where RAPD markers represent an accurate tool for determining genetic variation and for resolving relationships among populations