Clonal nature of gynogens induced from spontaneous diploid eggs in the loach, Misgurnus anguillicaudatus

In the leach, Misgurnus anguillicaudatus, diploid individuals (2n = 50) are common in Japan, but a small number of natural triploids (3n = 75) also ha ve been found. A previous paper reported that samples collected from the fi sh farm in the Niigata Prefecture exhibited a relatively high proportion of triploidy. In the same locality, a diploid leach which laid both diploid a nd haploid eggs was found by examining the viability of gynogenetically ind uced progeny. In the present work, we examined DNA fingerprints of gynogene tic diploid progeny developed from diploid eggs fertilized with UV-irradiat ed spermatozoa, using oligonucleotide probes (GACA)(4), (GGAT)(4) and 33.15 . Control diploids from normal fertilization (2n x 2n) showed individual sp ecific DNA fingerprints with band sharing indices (BSI) ranging from 0.51 t o 072. Gynogenetic diploid progeny (2n x UV) exhibited DNA fingerprints, id entical (BSI = 1) or quite similar (BSI = 0.94-0.98) to those of the mother fish. These results indicate that spontaneous diploid eggs are clonal or n ear clonal, suggesting the involvement of unreduced egg formation such as p remeiotic endomitosis.