Shape and size variation on the wing of Drosophila mediopunctata: influence of chromosome inversions and genotype-environment interaction.
The second chromosome of Drosophila mediopunctata is highly polymorphic for inversions. Previous work reported a significant interaction between these inversions and collecting date on wing size, suggesting the presence of genotype-environment interaction. We performed experiments in the laboratory to test for the joint effects of temperature and chromosome inversions on size and shape of the wing in D. mediopunctata. Size was measured as the centroid size, and shape was analyzed using the generalized least squares Procrustes superimposition followed by discriminant analysis and canonical variates analysis of partial warps and uniform components scores. Our findings show that wing size and shape are influenced by temperature, sex, and karyotype. We also found evidence suggestive of an interaction between the effects of karyotype and temperature on wing shape, indicating the existence of genotype-environment interaction for this trait in D. mediopunctata. In addition, the association between wing size and chromosome inversions is in agreement with previous results indicating that these inversions might be accumulating alleles adapted to different temperatures. However, no significant interaction between temperature and karyotype for size was found--in spite of the significant presence of temperature-genotype (cross) interaction. We suggest that other ecological factors--such as larval crowding--or seasonal variation of genetic content within inversions may explain the previous results.
Hatadani
Luciane Mendes
LM
Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Cx. Postal 6109, Campinas 13083-970, SP, Brazil. hatadani@unicamp.br
Klaczko
Louis Bernard
LB
D000704:Analysis of Variance; D000818:Animals; D007446:Chromosome Inversion / Q000235:genetics*; D016002:Discriminant Analysis; D004330:Drosophila / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics*; D004777:Environment; D005260:Female; D005838:Genotype; D007621:Karyotyping; D008297:Male; D015203:Reproducibility of Results; D012733:Sex Differentiation; D013696:Temperature; D014921:Wings, Animal / Q000033:anatomy & histology*