Rita Alicchio

Genetic Variability in Experimental Populations of Drosophila Melanogaster

Ital J Zoology, 1972

Somaclonal Variation in Eggplant (Solanum melongena L.)

Biotechnology in Agriculture and Forestry, 1990

Phenotypic variability and divergence in disruptive selection

Theor Appl Genet, 1974

Two types of disruptive selection (HL and LH) were performed on three lines (M, F and K) which ha... more Two types of disruptive selection (HL and LH) were performed on three lines (M, F and K) which had reached different plateaus, following a previous directional selection applied independently on the two sexes. Increase in phenotypic variability and the appearance of a bimodal frequency distribution of wing length measurements were considered as responses to disruptive selection.These responses are shown not to be linearly related; moreover both responses seem not to be related to the genetic and phenotypic variability present in the population when disruptive selection was started.These results and the persistent differences between LH and HL selections are interpreted as to suggest that the effects of disruptive selection are mainly dependent on changes in the developmental patterns of the genes involved and of their connections.The suggestion is advanced that the results presented are inconsistent with the assumption that the effects of disruptive selection be explained by genetic or developmental switch mechanisms or by chromosomal polymorphism.

Genetic Control of Body Traits and Growth Pattern in Lebistes

Canadian Journal of Genetics and Cytology, 1981

Genetic variability and growth pattern of metric traits were studied in inbred lines of Lebistes ... more Genetic variability and growth pattern of metric traits were studied in inbred lines of Lebistes reticulatus (Peters) obtained by crossing full sibs in three generations. Sub-sublines with different growth rates of body length and body weight were identified; on the whole inbred population a genetical analysis was performed for both traits at different ages on raw data and on data adjusted for growth rate regression. Both analyses reveal the presence of a great amount of genotype—environment interaction and of a certain amount of genetic variation for body traits. The differences concerning the genetic components of variation observed in the two analyses within each population indicate an influence of the different growth rates of sub-sublines on the detection of genetic variability.

Analysis in Isozymatic Patterns of Solanum melongena: Differences between Organized and Unorganized Tissues

Zeitschrift für Pflanzenphysiologie, 1981

Differential response to selection on the two sexes in Drosophila melanogaster

Genetics, 1973

Artificial selection for short wing was performed in two Drosophila melanogaster populations with... more Artificial selection for short wing was performed in two Drosophila melanogaster populations with partially different gene pools: the C populations were derived from a Canton stock while the H lines were derived from a cross between Canton and a b, cn, vg strain. It is shown that in both populations selection on females (CF, HF) was more effective than selection on males (CM, HM). This difference cannot be explained in terms of differences in additive genetic variability between the two sexes because: (1) both sexes contribute to the genetic variability utilized by selection applied to one sex only, and (2) switching selection pressure on females in the M lines does not result in a response comparable to that obtained in the F populations; this rules out almost completely recombination as the responsible agent for the differences between the selection limits reached by M and F selections.-These results, together with several additional observations concerning sexual dimorphism, fitn...

format_quoteSelection on females (CF, HF) produced greater wing length responses than males (CM, HM), with total gains reaching significant phenotypic standards.format_quote

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Phenotypic variability and divergence in disruptive selection

Theoretical and Applied Genetics, 1974

Two types of disruptive selection (HL and LH) were performed on three lines (M, F and K) which ha... more Two types of disruptive selection (HL and LH) were performed on three lines (M, F and K) which had reached different plateaus, following a previous directional selection applied independently on the two sexes. Increase in phenotypic variability and the appearance of a bimodal frequency distribution of wing length measurements were considered as responses to disruptive selection.These responses are shown not to be linearly related; moreover both responses seem not to be related to the genetic and phenotypic variability present in the population when disruptive selection was started.These results and the persistent differences between LH and HL selections are interpreted as to suggest that the effects of disruptive selection are mainly dependent on changes in the developmental patterns of the genes involved and of their connections.The suggestion is advanced that the results presented are inconsistent with the assumption that the effects of disruptive selection be explained by genetic or developmental switch mechanisms or by chromosomal polymorphism.

Interaction between artificial and natural selection

Theoretical and Applied Genetics, 1975

In order to understand how divergence may appear within a gene pool without limitations on gene f... more In order to understand how divergence may appear within a gene pool without limitations on gene flow, experiments were performed to investigate whether the genetic structure of a population may be effective in controlling the response to natural selection. Starting from plateaued populations of Drosophila melanogaster selected for wing length on the two sexes separately, the response to natural selection was studied after artificial selection had been discontinued. The results show that populations derived from artificial selection applied to the different sexes respond to subsequent natural selection in dissimilar ways, so as to suggest that the relationships between fitness and wing length have been changed. A second experiment comparing the response to natural and to artificial reversed selection suggests that different genes or gene complexes may be involved in wing length determination: these different genes show a dissimilar response in the different sexes and to natural and artificial selection. This variety of responses suggests that the interactions of different genes or gene complexes with artificial and natural selection could possibly lead to differentiation within the population.

Characterisation of cDNAs for ribulose bisphosphate carboxylase small subunit genes in different species of Avena ( Poaceae )

Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2000

... to the slow rate of nueleotide substitution in chloroplast genes as com-pared to plant and an... more

Genetic Heterogeneity and Disruptive Selection

Bolletino di zoologia, 1973

Genetic Control of Sexual Dimorphism in Drosophila Melanogaster

Bolletino di zoologia, 1975

Changes of sexual dimorphism values in Drosophila Melanogaster

Bolletino di zoologia, 1971

REED S. C., \VILLIAMS C. 11. and CIIADWICK L. E., 1042-Frequency of wing beat as a characfer for ... more REED S. C., \VILLIAMS C. 11. and CIIADWICK L. E., 1042-Frequency of wing beat as a characfer for separafing species, races and geographical varieties of Drosophila. Genetics, P i : 349-301. STunmvAhT A. &I., 1015-Experiments on sex recognifion and fhe problem of sexual selection i t 8 Drosoplula. J. h i m. Ueliav., 5 : 831-366.

format_quoteCorrelation coefficients tracked between sexual dimorphism and wing length show varied responses in relation to sex and selection pressure applied.format_quote

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Restriction fragment length polymorphism based phylogenetic analysis of Avena L

Genome, 1995

We report a molecular approach to the study of the phylogenetic relationships of Avena diploid an... more We report a molecular approach to the study of the phylogenetic relationships of Avena diploid and polyploid species based on RFLP detected with three cDNA probes of nuclear genes belonging to multigenic families (low pI α-amylase, avenin, and globulin). All the probes were highly informative in the detection of polymorphism between oat species. Associations between species were determined from cluster (UPGMA) analysis based on distance values calculated from RFLP data separately for each of the two levels of ploidy. Results were in general agreement with morphology based phylogenetic analyses, confirming the large differentiation among A and C genomes in the evolution of diploid species and the genetic homogeneity among A. brevis, A. strigosa, and A. nuda and the recently discovered A. atlantica. A certain divergence was observed between two endemic species (A. canariensis and A. damascena) and the other diploid species with the A genome. The analysis of tetraploid species relation...

Tissue cultures and plant regeneration from different explants in six cultivars ofSolanum melongena

Experientia, 1982

On the Evolutionary Consequences of Disruptive Selection

Bolletino di zoologia, 1973

ON THE EVOLUTIONARY CONSEQUENCES OF DISRUPTIVE SELECTION M o seopo di analizzare le eonseguenze e... more ON THE EVOLUTIONARY CONSEQUENCES OF DISRUPTIVE SELECTION M o seopo di analizzare le eonseguenze evolutive dells selezione divergente sono state considerate quattro linee di Drosophila melunoguster ottenute sia mediante selezionc direttiva (€111, LL) sin inediante selezione divergcnte (HL, LH) per la lunghezza del-I'nla. Dopo I'interruzione della selezione artificialc si instaura un process0 di selczione naturale die riduce la variabiliti delle popolazioni IIH e LL ottenute per selezione direttiva mentre non influenza la y-ariabilith delle popolazioni IIL e LII ottenute mediante selezione divergente.

format_quoteNatural selection reduces variability in populations HL and LL following artificial selection, while LH maintains differences post-selection.format_quote

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