Population Genetics of DROSOPHILA NASUTA NASUTA, DROSOPHILA NASUTA ALBOMICANA and Their Hybrids. I. Karyotypic Mosaicism in the Hybrid Populations.

D. n. nasuta and D. n. albomicana constitute a pair of chromosomal races with 2n=8 and 2n=6, respectively. The F(1) of these has 2n=7 and it is fertile. There exists a state of karyotypic mosaicism as evidenced by the presence of 26 types of chromosome combinations in F(2), F(3) and F(10) populations. In the midst of this karyotypic noise, the karyotype similar to that of F(1) reached 51% of the population. Implications of these findings are discussed.