Polygenic inheritance of background body colour in hybrids of Poecilia latipinna and Poecilia sphenops

Abstract

Inheritance of background body colour in molly, Poecilia is not well documented despite being an economically important aquarium fish. This study was attempted to understand the inheritance of background body colour between crosses of Poecilia latipinna (non-black) and Poecilia sphenops (black) through controlled breeding. A total of 13 breeding crosses which consist of two pure bred crosses, six parental hybrid crosses, two backcrosses, two test crosses and one full-sib cross were successfully initiated. In molly, Poecilia, non-black body colour is completely dominant over black and is not sex-linked. Multiple genes interaction which acted nonadditively was also found to be influencing this phenotypic trait. However, such interaction effect was restricted in crosses generated between genetically related fish (backcross and F2 full-sib) and was absent in crosses between distantly related fish (testcross). Perhaps, such occurrence was a natural mechanism to maintain the vibrancy of non-black colouration.