Estimation of genetic divergence and gene flow between Culex pipiens and Culex quinquefasciatus (Diptera: Culicidae) in Argentina
Mem. Inst. Oswaldo Cruz
;
93(1): 57-62, Jan.-Feb. 1998. mapas, tab
Article
Dans Anglais
| LILACS
| ID: lil-201994
RESUMO
Allele frequencies at seven polymorphic loci controlling the synthesis of enzymes were analysed in six populations of Culex pipiens L. and Cx. quinquefasciatus Say. Sampling sites were situated along a north-south line of about 2,000 km in Argentina. The predominant alleles at Mdh, Gpdh and Gpi loci presented similar frequencies in all the samples. Frequencies at the Pgm locus were similar for populations pairs sharing the same geographic area. The loci Cat and Hk-1 presented significant geographic variation. The latter showed a marked latitudinal cline, with a frequency for allele b ranging from 0,99 in the northernmost point to 0.04 in the southernmost one, a pattern that may be explained by natural selection (Fst=0.46;p<0.0001) on heat sensitive alleles. The average value of Fst(0.088) and Nm (61.12) indicated a high gene flow between adjacent populations. A high correlation was found between genetic and geographic distance (r=0.83;p<0.001). The highest genetic identity (In=0.988) corresponded to the geographically closest samples from the central area. In one of these localities Cx. quinquefasciatus was predominant and hybrid individuals were detected, while in the other, almost all the specimens were identified as Cx. pipiens. To verify the fertility between Cx. pipiens and Cx. quinquefasciatus from the northern- and southernmost populations, experimental crosses were performed. Viable egg rafts were obtained from reciprocal crosses. Hatching ranged from 76.5 to 100 per cent. The hybrid progenies were fertile through two subsequent generations.
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Culex
Limites du sujet:
Animaux
Pays comme sujet:
Amérique du Sud
/
Argentine
langue:
Anglais
Texte intégral:
Mem. Inst. Oswaldo Cruz
Thème du journal:
Médecine tropicale
/
Parasitologie
Année:
1998
Type:
Article
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