PgmNr D1407: The molecular difference between grey and black genotypes collected in Plopsoru village.

Authors:
G. A. Butnaru 1,2 ; I. Sarac 1 ; S. Popescu 1


Institutes
1) Banat Univ Agricultural Sci, Timisoara, Banat, RO; 2) Academy of Romanian Scientists.


Keyword: population variation

Abstract:

In 2010, from a sample of fruit flies collected from Plopsoru village a few individuals with a dark color and unusual behavior were separated. Plopsoru village represents a hilly-agro-ecosystem situated in miners’ area. After phenotypic checking the sample was split into two: a large grey group – Grey Plopsoru (GP) and few black individuals that generated a new “population” named Black Plopsoru (BP). The new genotype showed different morphological features: very dark black body and eyes, the size of wing imaginal discs at L3 significantly lower, eggs with 6-8 appendices, larval motility during the night, the pupae located in the cotton stopper and strong reproductive barrier for other Drosophila lines even for GP ecotype. In comparison to standard genotypes Oregon and white (w1118) and GP the life cycle of BP was longer with 99.2%, 120% and 108% respectively and emphasized a nocturnal behavior. For each ecotype successive generations were produced (six for BP and seven for GP). To establish the similarity vs. evolutionary distance among the analyzed Drosophila genotypes the ISSR (Inter Simple Sequence Repeat) and RAPD (Random Amplified Polymorphic DNA) markers were used. Therefore the polymorphism was emphasized randomly in genome and also for the segments located between microsatellites. It was pointed out that all of the selected markers (eight ISSR and four RAPD) generated a number of fragments ranged between 7 and 23 per primer. For all of the RAPD primers the similarity was 100%. All of the primers amplified 163 fragments of which 159 (97.5%) were polymorphic. The UPGMA (unweighted pair-group method) clustering method was used to establish the similarity coefficients and the dendrogram.

According to their genetic background the accessions of BP and GP were grouped in two main clusters, with a coefficient of similarity of 40.20±4.38%. In the first cluster all of the BP generations were grouped, with a very high similarity 96.96±1.13%. All of the GP generations formed the second cluster emphasizing a higher variability compared with BP, the similarity coefficient inside the group being 72.58±10.69. The highest and the lowest coefficients were 87.25% between first and fourth generations for BP, respectively 55.03% between second and sixth GP generations.  Therefore, two subclusters were separated, the first being made up from the first five generations and the second one from six and seven generations, pointing out a large distribution of the similarity coefficients. The molecular evaluation revealed the big difference between BP and GP even if they are the “product” of the same evolutionary conditions; BP pointed out a high stability in the offspring six generations.