| Dispersal is an important event in animal's life history,and has an important influence on population genetic structure and social relationship in the population.Ecological dispersal refers to the movement of individuals from one location to another.The reproductive status,habitat selection and environmental damage of underground rodents are closely related with their dispersal.It is of great significance to study the dispersal of underground rodents in order to control the damage and protect the biodiversity.Rodents exhibit a highly diverse pattern of dispersal,but it is difficult to study the dispersal patterns of underground rodents because they inhabit under the ground.In this study,8 microsatellite loci were used to study the dispersal patterns and spatial genetic structure of 5 Rattus losea populations in neighbouring island,and the main results were as follows:1.A total of 95 alleles were detected in 168 individuals,and the average number of alleles was 12.The observed heterozygosity was significantly higher than expected heterozygosity,the average observed heterozygosity was 0.936 and the average expected heterozygosity was 0.847.The population of Rattus losea has a high genetic diversity,the average polymorphic information content was 0.826.Departures from Hardy-Weinberg equilibrium were found in 8 microsatellite loci.2.The degree of genetic differentiation among the populations was low,five populations were clustered into three branches,the Damao island population and the Xiaomao island population were in one branch,the Dazhairuo mountain population and the Xiaozhairuo mountain population were in another branch,and the Xiaopanzhi island population was in a single branch.3.Using the assignment test,34 dispersers were detected in 168 individuals,accounting for 20% of the total number of individuals.The dispersal rates of the five populations in Xiaopanzhi island,Xiaozhairuo mountian,Dazhairuo mountian,Damao island and Xiaomao island were 8.11%(3/37),14.81%(4/27)and 35.71%(10/28),34.29%(12/35),13.89%(5/36),respectively.The Dazhairuo population had the largest dispersal range,and the dispersers were found in the other four populations.The higher dispersal frequency was found,between the Dazhairuo population and the Xiaozhairuo population,as well between the Damao population and the Xiaomao population.4.The sex-biased dispersal results(1)F-statistic analysis showed that the genetic differentiation coefficient of male(Fst = 0.076)was higher than that of female(Fst = 0.058)at all loci.The inbreeding coefficient between males(Fis =-0.234)was lower than that of females(Fis =-0.207).(2)Assignment test showed that the corrected assignment index was 0.068 among female individuals and-0.08 among male individuals.(3)The distance isolation test showed that there was a significant positive correlation between the genetic distance and the geographical distance of the female individuals(P < 0.05),while there was a negative correlation of the male individuals(P > 0.05).Based on the three methods,the Rattus losea population was male-biased dispersal.5.Spatial genetics demonstrated that there was a non-random spatial genetic structure among Rattus losea individuals in Zhoushan archipelago,and it was inconsistent with the geographical isolation model.Spatial autocorrelation analysis showed that the spatial scale of the genetic similarity occurred in the range of 2.5 km distance,which showed that the spatial scale had positive autocorrelation coefficient in the short distance scale.In the three age groups,the juvenile group showed a non-random distribution of spatial genetic structure in the short distance scale,which indicated that the juvenile was the main dispersers in our sampling periods. |
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