Preprint volume - SIBM

Pre-print Volume - Oral presentations
Topic 2: MARINE ORGANISMS AND ECOSYSTEMS AS MODEL SYSTEMS
sequenced. Seven microsatellite loci (Nagai et al., 2006) were used to genotype all A.
minutum isolates. Samples were amplified in an Applied Biosystems DNA Thermo
Cycler 2720 (Applied Biosystems Inc., USA). Each PCR product was visualized on
agarose gel 2.5% (w/v), analyzed by ABI PRISM 3100-Avant Genetic Analyzer
(Applied Biosystem, USA) and finally sized by GeneMapper software ver. 4.0
(Applied Biosystems Inc., USA). The global and pairwise genetic diversity and
fixation indices (FST), and Analysis of Molecular Variance (AMOVA) among the
different populations were calculated by the Arlequin software ver. 3.1 (Excoffier et
al., 2005) and Fstat software ver. 2.9.3 (Goudet, 2001). The Principal Coordinate
Analysis (PCoA) based on the genetic distance matrix was carried out by the Excel
application GenAlEx ver. 6.1. Bayesian analyses were performed using Structure
software ver. 2.2 (Pritchard et al., 2000).
Results - The alignment of the 5.8S-ITS rDNA sequences showed a nucleotide
sequence identity of 100% among all A. minutum isolates. The seven primers used for
the PCR amplification of 7 microsatellite loci of A. minutum isolates provided PCR
amplified products of the expected range size. The different genetic diversity indices
within population of A. minutum (Tab. 1) indicated that all loci were polymorphic in all
the sampling stations and showed a number of alleles ranging from 2 to 12. The allelic
richness varied from 3.64±1.29 to 7.17±0.80 and the gene diversity from 0.62±0.17 to
0.89±0.04.
Tab. 1 – Genetic variability of A. minutum based on seven microsatellite loci.
Variabilità genetica di A. minutum stimata per sette loci microsatelliti.
N. ADRIATIC C. ADRIATIC IONIAN
CLUSTERS
TYRRHENIAN CATALAN BALEARIC ATLANTIC
N 8.71±0.76 20.00±2.94 17.29±1.70 22.86±1.68 20.29±1.89 10.57±1.13 8.57±0.53
Na 5.14±1.35 9.43±1.18 4.14±1.46 5.57±1.99 4.43±2.30 4.00±1.41 4.57±0.53
GD 0.87±0.07 0.89±0.04 0.62±0.17 0.71±0.14 0.62±0.28 0.71±0.13 0.74±0.12
Ar 5.07±1.37 7.17±0.80 3.64±1.29 4.57±1.57 3.68±1.64 3.84±1.39 4.49±0.54
N, number of individuals; Na, number of alleles observed per locus; GD, gene diversity; Ar, allelic richness.
N, numero di individui; Na, numero di alleli osservati per locus; GD, diversità genetica; Ar, ricchezza
allelica.
The global FST index, reached a value of 0.19 (p