The Significance of Genetic Polymorphisms within and between Founder Populations of Ceratitis capitata (Wied.) from Argentina

Abstract

BackgroundThe Mediterranean fruit fly Ceratitis Capitata (DIPTERA: Tephritidae) is a major agricultural pest in Argentina. One main cause for the success of non-contaminant control programs based on genetic strategies is compatibility between natural and laboratory germplasms.A comprehensive characterization of the fruit fly based on genetic studies and compatibility analysis was undertaken on two founder populations from the provinces of Buenos Aires and Mendoza, used in pioneering sterile male technique control programmes in our country. The locations are 1,000 km apart from each other.Methodology/Principal FindingsWe compared the genetic composition of both populations based on cytological, physiological and morphological characterization. Compatibility studies were performed in order to determine the presence of isolation barriers. Results indicate that the Buenos Aires germplasm described previously is partially different from that of the Mendoza population. Both laboratory colonies are a reservoir of mutational and cytological polymorphisms. Some sexual chromosome variants such as the XL and the YL resulting from attachment of a B-chromosome to the X-chromosome or Y-chromosome behave as a lethal sex-linked factor. Our results also show incompatibility between both germplasms and pre-zygotic isolation barriers between them. Our evidence is consistent with the fact that polymorphisms are responsible for the lack of compatibility.ConclusionsThe genetic control mechanism should be directly produced in the germplasm of the target population in order to favour mating conditions. This is an additional requirement for the biological as well as economic success of control programs based on genetic strategies such as the sterile insect technique. The analysis of representative samples also revealed natural auto-control mechanisms which could be used in modifying pest population dynamics.

Analysis of survival, gene expression and behavior following chill-coma in the medfly Ceratitis capitata: Effects of population heterogeneity and age

“…This strain was originally isolated as a colony of several individuals from a very polymorphic Argentinean population (Basso et al, 2009), and after about 300 generations, a significant degree of genetic heterogeneity still persists in our laboratory population. For the experiments, virgin adult flies were collected less than 12 h after emergence from the puparium, sexed under CO 2 anesthesia, and placed in 3.75 L flasks with free access to sucrose: dry yeast (3:1) and 1% agar as sources of food and water, respectively.…”

Autosexing strains to control populations of fruit flies (DIPTERA: Tephritidae): why do they fail to succeed?

“…14 A limiting factor for the success of the sterile male technique is compatibility between natural and laboratory populations. 10,14 The purpose of this work is to dissect the reasons why these methods recurrently fail to succed.…”

Reference Karyotypes and Chromosomal Variability: A Journey with Fruit Flies and the Key to Survival

“…The analysis of genetic variation within and between natural populations of C. capitata [15] explains the history of our reference laboratory strain Arg 17 as well as all the morphological, chromosomal, and physiological variants along with the study of Mendoza polymorphisms colonies used in control strategies [15,16]. We now summarize the chromosomal mutations found in the species throughout the years: reciprocal translocations, multiple translocations, and translocations between a sex chromosome and an autosome.…”

“…The transmission of the Y + B = Y L was analyzed in Ref. [15]. The deletions affecting the long arm of the sexual Y chromosome produces a mutant Y named Y B [15].…”

“…The polymorphism Ya-Yb is analyzed in Ref. [15]. Other chromosomal mutations were also isolated in different families such as inversions involving the autosomes, sexual aneuploidies: sexual trisomics 2n = 2x + 1 = 13 XXX, XXY, and sexual tetrasomics 2n = 2x + 2 = 14 XXYY.…”