Francisco Perfectti

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Six populations of the fish Prochilodus lineatus were analysed for B chromosome frequency. A study of spermatogenesis revealed the absence of B accumulation during the stages analysed. In one of the populations, from the Mogi-Guaçu river where samples have been analysed over a ten-year period, B chromosome frequency doubled between 1979-80 and 1987 89,(More)
Analysis of chromosome localization of three molecular markers, 18S-5.8S-28S rDNA, 5S rDNA and a 180 bp satDNA, showed that B chromosomes in the grasshopper Eyprepocnemis plorans originated independently in Eastern (Caucasus) and Western (Spain and Morocco) populations. Eastern B chromosomes are most likely derived from the smallest autosome, which is the(More)
The genetic basis of host preference has been investigated in only a few species. It is relevant to important questions in evolutionary biology, including sympatric speciation, generalist versus specialist adaptation, and parasite-host co-evolution. Here we show that a major locus strongly influences host preference in Nasonia. Nasonia are parasitic wasps(More)
A centric fragment was generated during the introgression of a chromosome region from Nasonia giraulti into N. vitripennis. This neo B chromosome carries the N. giraulti or 123+ gene for wild-type eye color. Using this phenotypic effect, the transmission of this chromosome was analyzed. The supernumerary chromosome showed less than Mendelian segregation(More)
The double FISH analysis of two repetitive DNAs (a satellite DNA and ribosomal DNA) in 12 natural populations of the grasshopper Eyprepocnemis plorans collected at the south (Granada and Málaga provinces) and south-east (Albacete and Murcia provinces) of the Iberian Peninsula has shown their wide-spread presence throughout the whole genome as well as(More)
The chromosomal localization of ribosomal DNA, and a 180 bp satellite DNA isolated from Spanish Eyprepocnemis plorans specimens, has been analysed in five Eyprepocnemidinae species collected in Russia and Central Asia. Caucasian E. plorans individuals carried each of the two DNAs, but the rDNA was limited to only two chromosomes (S(9) and S(11)) in sharp(More)
The transmission of the B1 chromosome through females has been analysed in three Moroccan populations (Smir, SO.DE.A. and Mechra) of the grasshopper Eyprepocnemis plorans. We analysed transmission ratio (kB) variation at two levels: intra-individual (to test female age effects) and inter-individual (to test for A chromosome effects). In 81.8% of females, kB(More)
B chromosomes are genome symbionts, the presence of which in many eukaryote species is explained, in most cases, by their violation of Mendelian rules, usually based on meiotic or mitotic instability, leading to their accumulation in the germ line (drive). However, B chromosome integration into the genome as a regular member of the chromosome set should(More)
Parasites and hosts are involved in a continuous coevolutionary process leading to genetic changes in both counterparts. To understand this process, it is necessary to track host responses, one of which could be an increase in sex and recombination, such as is proposed by the Red Queen hypothesis. In this theoretical framework, the inducible recombination(More)
Extensive variation in the size of the short (heterochromatic) arm of chromosome 14 was found in the wasp Trypoxylon (Trypargilum) albitarse. Ten different variants were differentiated by size and C-banding pattern. Fluorescent in-situ hybridization (FISH) revealed that ribosomal DNA in this species is clustered in the darkly C-banded parts of the(More)