The Analysis On Genetic Structure Of Four Different Areas Tilapia Populations

1. RAPD technique was used to analyze the genetic structure and forecast fish heterosis of four different areas of tilapia populations. In all 20 random primers, 12 random primers were chosen out and used to amplified the individuals?genomic DNA of four Tilapia populations (Fo is token FFRC O.uureus, Sn: Shashi O.niloticus; En: Egyptian O.niloticus; Eo: Egyptian O.uure us). The 12 primers all generated amplification bands, whose numbers ranged from I to 8 and sizes from 500-2300bp. By analyzing the data of the genetic fingerprints, the genetic relationship of the four tilapia populations was constructed with UPGMA. The result of this experiment showed the fact as follow: the with-population index of similarity of Fo, Sn, En and Eo calculated from RAPD fingerprints were respectively 0.853,0.706,0.592 and 0.667.The between-population index of genetic distance of them were that Fo and Sn was 0.577, Fo and En was 0.450, Fo and Eo was 0.386, Sn and En was 0.368, Sn and Eo was 0.466. En and Eo was 0.400. From the data it was safely to arrive the conclusion that the genetic quality of Fo was more pure than the rest of the four populations?and there were still some genetic diversity of En and Eo. It suggested that if they were chosen properly, they were all good breeding resources. At the same time, according to the data of between-population 3 ABSTRACT index of genetic distance, it could be predicted that Fo( ~ ) X Sn( ~) should have a more advanced beterosis. 2. 11aditional morphological data was used to analyze the morphological variations of the four tilapia populations from different areas. Traditional morphological data and comparable characters were combined to conduct a multivariation analysis to study the morphological variations of four tilapia populations. Analysis of meristic characters and comparable characters in whole indicated that there were no significant differences among these populations, but in the comparable characters, there were four parameters among the four populations existed significant differences. From the result, it could be informed that the two Egyptian populations were longer than the others in length. It was caused possibly by the following two reasons: CD Different geographic populations were undergone different circumstance factors;甌he select tendency of local people were also very important.