Structure génétique des cécidomyies des céréales en Tunisie

Genetic structure of Hessian flies in Tunisia. The genetic structure of M. destructor and M. hordei was investigated by sampling 21 fields of cereals in 14 localities of central and southern Tunisia. As previously shown, there was no strict association between the cereal species (wheat, barley and oat) and the Mayetiola species. M. destructor males displayed no heterozygosity at the Pgm3 locus, indicating that they were hemizygous as is the PGM locus in North America. In M. hordei, heterozygous males were observed at all loci, but strong heterozygote deficits were found at two loci (Mdh2 et Hk). Since no such deficit was observed in females, the population structure of M. hordei was studied only in females. Although heterozygosity was two fold higher in M. hordei than in M. destructor, the two species were similar for other genetic characteristics, including a low (Fst < 0.05) but significant (P < 0.05) genetic differentiation, no isolation by distance, and similar rates of gene flow (5.7 ≤ Nm ≤ 9.6). These results are discussed in relation to their consequences in the event of controlling Tunisian Hessian flies using wheat cultivars that are resistant to a M. destructor biotype.     

Variations de la malate déshydrogénase dans quatre espèces de Jaera albifrons: Etude génétique et variation géographique

Malate dehydrogenase has been detected in four species of the super-species Jaera albifrons. Two polymorphic enzymatic systems occur showing a one banded pattern for homozygotes and a three banded pattern for heterozygotes. Two independant autosomal loci control the variation as is shown by intra- and interspecific crosses. In European populations of the three species studied, MDH-1 is polymorphic and MDH-2 is monomorphic. In the American species, J. posthirsuta, the locus MDH-2 is polymorphic and MDH-1 is monomorphic.     

Premier apport de la génétique biochimique des populations à la systématique des mulots de France continentale et de corse

An electrophoretic survey of enzymes coded at 15 loci in field mouse populations showed the existence of two biochemical groups whch are reproductively isolated, Apodemus sylvaticus A. flavicollis. The diagnostic loci which identify each species as well as the intra- and interspecific genetic distances show that hybridization does not occur in localities where they are sympatric.