RAPD analysis for natural population genetic structure of Carya cathayensis

Random amplified polymorphic DNA(RAPD)markers were used to measure genetic diversity and genetic structure of 150 individuals from 5 natural populations of Carya cathayensis.252 loci were identified from 20 RAPD primers,out of which 168 loci were polymorphic and accounted for 66.7% of the total genetic diversity at species level.Shannon′s information index(I)varied from 0.199 2 to 0.280 0,and Nei′s gene diversity index(H)varied from 0.129 7 to 0.205 1 at population level,with I=0.410 2 and H=0.267 1 at species level.Gst analysis showed 0.384 5 genetic variation among populations,which indicated that most of the variation(61.55%)existed within populations.Nm=0.967 1,which showed that the gene flow among populations was at relatively low level.An analysis of molecular variance(AMOVA)also showed 0.341 3 differentiation among populations.The results above were consistent with the characteristics that C.cathayensis was an outcrossing and wind-pollinated plant,but its genetic differentiation parameters were a little higher than the mean value among populations of outcrossing and wind-pollinated plants(Gst=0.193 0).The possible reasons for the genetic diversity and genetic structure of C.cathayensis at present were mainly related to the geographic isolation,inbreeding and limited gene flow.