PARENT SESSION
5C Ecological relevance of endocrine disruption
9:00 AM to 7:00 PM, Tuesday, 08 May 2001
Session Chair:

(T/MF209) Molecular characterisation of Dumpton Syndrome in Nucella lapillus L. using random amplified polymorphic DNA (RAPD).

Quintela, Maria¹, Barreiro, Rodolfo¹, Ruiz, José Miguel¹, ¹

ABSTRACT- Dumpton Syndrome (DS) is a genetic aberration that causes aphally in males of the marine gastropod N. lapillus and also lessens the expression of imposex in females from TBT-polluted areas. RAPD markers were used to assess the molecular difference between normal and DS-affected males because they provide a powerful tool for investigating the genetic variation at different levels of organisation. Three ras were sampled along the coast of Galicia (NW Spain); two locations per ra and five to ten males per site were screened. DNA extraction was performed using CTAB method modified for DNA miniprep from foothead of the animal. After a preliminary study using 80 decamer primers, six of them were selected which showed polymorphism for Dumpton Syndrome. RAPD markers were scored based on the presence/absence of the bands. Most markers were polymorphic, and several analysis were performed. Estimates were made for the proportion of polymorphic markers and Shannon genetic diversity index. Further, a similarity matrix (Jaccard coefficient) was calculated followed by AMOVA and UPGMA cluster. The correlation between genetic and geographic distances was assessed by Mantel correlogram. The proportion of polymorphic bands within ras ranged from 20 to 57%. Nearly 37% of the variation was found among ras, 27% to populations within ras and 36% among individuals within sites. Genetic and geographic distances were significantly correlated (r=0.7875, P=0.0005). The UPGMA cluster revealed a clear difference among ras. Still within ras, populations from two sampled sites were considerably different. Where DS-affected individuals were present, normal and aphallic males differed to a great extent and formed neatly distinct clusters.

Key words: Nucella lapillus, imposex, RAPD, Dumpton Syndrome