Genetic analysis of parthenogenetic capability and fecundity in Drosophila albomicans

Abstract

Background: The successful rate of parthenogenesis in Drosophila harvested from natural population was extremely low, which could be effectively improved under selection pressure. Facultative parthenogenesis in Drosophila albomicans may be advantageous for its expansion from sub-tropical to temperate area. Since the understanding of the genetics involved in the capability and fecundity of parthenogenesis is limited, this study aims to preliminarily map the chromosome regions that are preferentially important for parthenogenesis. Results: Genetic mapping was performed with F-2 individuals that were parthenogenetically produced by F-1 from crosses between a parthenogenetic strain KKU119 and a sexual strain #55.1 of Drosophila albomicans. Among 105 F-2, 53.3% of them had parthenogenetic capability which is highly associated with three markers a28, c4081, and c7198 located near or inside In(2L)B1D5. A sexual strain with high In(2L)B1D5 heterozygosity originating from Wulai, Taiwan in 1970 was able to perform parthenogenesis. However, the fecundity of those F-2 varied in a wide range, forming a continuous distribution as expectation of a quantitative trait and was correlated with the number of homozygous markers for all markers on the second chromosome and neo-X chromosome arm. Conclusions: We have genetically analyzed the capability and fecundity of parthenogenesis in Drosophila albomicans. The former is specifically associated with a limited region in the B-1 to D-5 of 2L arm where inversion In(2L)B1D5 may play certain role for the maintenance of parthenogenesis, whereas the latter is apparently related to several quantitative loci on the second chromosome and neo-X chromosome arm.