Developmental And Genetic Analysis Of The Hybrids Between Paralichthys Olivaceus(♀) And Verasper Variegatus(♂)

In this study, distant interfamilial hybridization between female P. olivaceus and male V. variegatus was done. The embryonic and larvae development of the hybrid was observed. Chromosome observation and karyotype analyse in paternal V. variegatus and hybrid were undertaken and compared with that of P. olivaceus to confirm the hybrid nature. The status of polymorphism, the inheritance and segregation patterns of molecular markers from parents to hybrids were analyzed by ISSR marker. The unique inherited characteristics of ITS1 in the hybrids were revealed. The main results of this study are as follows:1 , The early development of hybrid was observed and the morphological characteristics of each developmental stages were described. The fertilization rate, hatching rate and deformity rate were 71.18% ±0.14, 61.65%±0.19, 17.00%±0.06, respectively. The survival rate of the hybrid was 58.63%±0.19 from hatching to first feeding, and 57.08%±0.20 from first feeding to metamorphosis, respectively. Under water temperature (15±0.5)°C and salinity 29-30, the hatch-out of fry began at 74 h after fertilization and the mouth opened on the 4^th day post hatched. The metamorphosis completed on about the 35^th days post hatched. During metamorphosis, eye position of the hybrid was mixed with both dextral (37%) and sinistral type (63%). The results indicated that the gametes from P. olivaceus and V. variegatus can fertilize easily with no incompatibility. The development and survival potential were all comparable with those of maternal parent P. olivaceus.2, The chromosome of P. olivaceus was reported to be 2n = 48 t. In the present study, chromosome observations showed that the karyotype of V. variegates was 2n = 46 = 4 sm + 42 t while was apparently different from that of P. olivaceus owing to the existence of 2 pairs of submetacentric chromosomes. Detailed analysis showed that the karyotype of hybrid was 2n = 47 = 2 sm + 45 t. The presence of the 2 submetacentric...