In order to assess the occurrence of temporal variations in the genetic structure of populations of Hediste diversicolor, 4 intertidal sites (10 m2 wide) were located in two estuaries of the North-eastern and North-western Adriatic and Tyrrhenian coasts of Italy (Pialassa and Serchio) and were repeatedly sampled from 2001 to 2003. Temporal genetic changes were investigated at 6 allozyme loci (ALD, FH, HBDH, LDH, PGI and SDH). Allelic frequencies, percentages of polymorphic loci, mean observed and expected heterozygosities varied both between sampling times and among sites. At each site, FST values revealed significant temporal changes between sampling times. The observed temporal genetic variability along with patterns of genetic fragmentation previously described suggest the occurrence of “chaotic genetic patchiness” within estuaries. Results support the model proposed by Authors who, analysing population dynamics and secondary production of H. diversicolor, hypothesised that variations in densitydensities of H. diversicolor are related to heavily affected by periodical mortality events followed by local recruitment. Genetic drift, related to mortality events, and/or sweepstake reproductive success appear to be microevolutionary and ecological processes promoting the genetic structuring of H. diversicolor within estuaries.
Temporal changes in the genetic structure of intertidal populations of Hediste diversicolor (Polychaeta: Nereididae)
ABBIATI, MARCO
2006
Abstract
In order to assess the occurrence of temporal variations in the genetic structure of populations of Hediste diversicolor, 4 intertidal sites (10 m2 wide) were located in two estuaries of the North-eastern and North-western Adriatic and Tyrrhenian coasts of Italy (Pialassa and Serchio) and were repeatedly sampled from 2001 to 2003. Temporal genetic changes were investigated at 6 allozyme loci (ALD, FH, HBDH, LDH, PGI and SDH). Allelic frequencies, percentages of polymorphic loci, mean observed and expected heterozygosities varied both between sampling times and among sites. At each site, FST values revealed significant temporal changes between sampling times. The observed temporal genetic variability along with patterns of genetic fragmentation previously described suggest the occurrence of “chaotic genetic patchiness” within estuaries. Results support the model proposed by Authors who, analysing population dynamics and secondary production of H. diversicolor, hypothesised that variations in densitydensities of H. diversicolor are related to heavily affected by periodical mortality events followed by local recruitment. Genetic drift, related to mortality events, and/or sweepstake reproductive success appear to be microevolutionary and ecological processes promoting the genetic structuring of H. diversicolor within estuaries.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
