Chromosome - site interaction in the South American fruit fly Anastrepha fraterculus (Wied.)
The present paper aims to further analyze and explain which is the significance of genetic variation in the so-called Anastrepha fraterculus complex and to solve if chromosomal vari-ants in Anastrepha fraterculus are associated to geographic variation. Our hypothesis are: I) chromosomal variants are...
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| Otros Autores: | , |
| Formato: | Artículo |
| Lenguaje: | Inglés |
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| Acceso en línea: | http://ri.agro.uba.ar/files/download/articulo/2019basso.pdf LINK AL EDITOR |
| Aporte de: | Registro referencial: Solicitar el recurso aquí |
| Sumario: | The present paper aims to further analyze and explain which is the significance of genetic variation in the so-called Anastrepha fraterculus complex and to solve if chromosomal vari-ants in Anastrepha fraterculus are associated to geographic variation. Our hypothesis are: I) chromosomal variants are not randomly distributed in the South American fruit fly populations studied. II) Chromosomal variants are not reproductive isolation markers. We sampled guava fruits from Argentina, Uruguay and Brazil during at least two years, to recover Anastrepha larvae as well as adult flies. The latter were single pair mated to form laboratory strains. We studied the chromosomal pattern of 879 larvae from wild populations and derived laboratory strains. Sexual chromosome variants were associated to different strains. Banding patterns were obtained with routine and molecular cytogenetics. Strains from the most distant localities were used in crossings. We computed a log lineal analysis of the data set in order to test the hypothesis of inertia and to get probabilistic estimates of relevant parameters associated with chromosome variation. We used a test of hypothesis to determine the existence of statistically significant associations between karyotypic frequencies relative to sex chromosome variants and the natural populations. With respect to hypothesis I, analyses showed ten sexual chromosome variants [(X1, X2, X3, X4) and (Y1, Y2, Y3, Y4, Y5, Y6)] and highly significant statistical chromosome site interaction, i.e. significant differentiation between observed data and those merely expected from random association of chromosome types with localities (inertia). When large samples from a given population were available, eight out of ten variants were found. With respect to hypothesis II, we could detect 28 different sexual karyotypes out of 34 possible combinations and it seems that no chromosome variant operates as a reproductive isolation marker. Our evidence is consistent with our previous suggestions, demonstrating that – within the regions studied- A. fraterculus is a single polymorphic species. |
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| ISSN: | 2572-8466 |