Alcohol dehydrogenase activities and ethanol tolerance in Anastrepha (Diptera, Tephritidae) fruit-fly species and their hybrids.

Eneas Carvalho,Vera Nisaka Solferini,Sergio Russo Matioli

doi:10.1590/s1415-47572009005000012

Eneas Carvalho, Vera Nisaka Solferini + Show 1 more

Open Access

https://doi.org/10.1590/s1415-47572009005000012

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Abstract

The ADH (alcohol dehydrogenase) system is one of the earliest known models of molecular evolution, and is still the most studied in Drosophila. Herein, we studied this model in the genus Anastrepha (Diptera, Tephritidae). Due to the remarkable advantages it presents, it is possible to cross species with different Adh genotypes and with different phenotype traits related to ethanol tolerance. The two species studied here each have a different number of Adh gene copies, whereby crosses generate polymorphisms in gene number and in composition of the genetic background. We measured certain traits related to ethanol metabolism and tolerance. ADH specific enzyme activity presented gene by environment interactions, and the larval protein content showed an additive pattern of inheritance, whilst ADH enzyme activity per larva presented a complex behavior that may be explained by epistatic effects. Regression models suggest that there are heritable factors acting on ethanol tolerance, which may be related to enzymatic activity of the ADHs and to larval mass, although a pronounced environmental effect on ethanol tolerance was also observed. By using these data, we speculated on the mechanisms of ethanol tolerance and its inheritance as well as of associated traits.

Highlights

The alcohol dehydrogenase enzyme system (ADH) of Drosophila is a classical model used in understanding the question of the evolutionary relevance of enzyme polymorphism
We used Anastrepha flies as models for ADH studies, owing to their remarkable ability to undergo viable inter-specific crosses between species that express different numbers of Adh copies and with differences in ADH related traits, a feature rarely observed in Drosophila
We ended up with five groups to work with: A. fraterculus, A. obliqua, hybrid, backcross 1 and backcross 2

Summary

Introduction

The alcohol dehydrogenase enzyme system (ADH) of Drosophila is a classical model used in understanding the question of the evolutionary relevance of enzyme polymorphism. The ADH system of Anastrepha is similar to that of Drosophila in its electrophoretic patterns, the dimeric composition of the functional enzyme and the differential tissue and life stage expression of loci (Matioli et al, 1986, 1992; Nascimento and Oliveira, 1997). Their ADH enzymes seem to have evolved independently from a common ancestral gene (Ashburner, 1998). The parents, both hybrids and backcrosses, constitute groups with differences in both the number of Adh loci and their genetic background We considered this as an interesting model for studying the relationship between the ADH system and ethanol metabolism and tolerance. The parameters analyzed were (1) phenotype/physiological factors (ADH activities, larval protein content and ethanol tolerance), (2) environmental factors (exposure time and ethanol concentration) and (3) genetic factors (genetic background composition)

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