Microsatellite Makers Reveal Genetics Of Coral In The South China Sea.

Impacted by both anthropogenic activities and climate change,coral reefs in the South China Sea have declined markedly.Porites lutea located extensively at both low latitudes and relatively high latitudes and Pocillopora damicornis are mainly distributed in low latitudes and are sensitive to temperature.This study chose P.lutea and P.damicornis to study in genetic diversity,genetic structure and population connectivity in different latitudes coral reeds in the SCS,which will contribute to manage reef resources under the increasing environmental disturbance.Microsatellite markers of Porites have been developed and well established in practice,but P.damicornis lack microsatellite markers.Artificial bleaching was conducted to get the less contaminated P.damicornis gemone and chose high-throughput sequencing to the development of P.damicornis microsatellite.In addition,this study get a further study in the levels of genetic diversity,population structure,the relationship between detailed genetic structure and different latitude,the possible factors to affect genetic variation and the patterns of reproduction in SCS P.lutea populations in 14 P.lutea populations at large scale in the SCS and estimate following hypotheses by MLGs generated from the nine polymorphic microsatellites.The main results as follow:1)This study used high-throughput sequencing to the development of P.damicornis microsatellite,obtained 2786 microsatellite loci and examined 7 polymorphic markers in Luhuitou P.damicornis population.This fill the blank of the microsatellite loci in P.damicornis and provide new technical support for the further study of coral genetics in the SCS.2)In this study,the collections of SCS govern a high proportion of unique multi-locus genotypes(N/Ng,mean = 0.99±0.13),indicating that almost all P.lutea propagates by sexual reproduction in SCS.The sexual reproduction of corals are known to generate abundant multi-locus genotypes in coral communities,which idicated P.lutea have the high genetic potential.3)Genetic diversity of Daya Bay was lower compared to other latitude P.lutea populations,with the lowest values found in Xiaolajia.It is possible due to its marginal nature of habitat(low temperature in winter)and latitudinal diversity gradient.4)Geographic distance explained 16.12%of the variation in genetic distance in the SCS,which meant geographical isolation has little effect on genetic variation,but SST fluctuations in different latitude possible has an impacted on P.lutea population structure and thereby cause genetic variation between relatively high latitude and low latitude coral populations.5)Pairwise FST values derived from microsatellite markers indicated the relatively high latitude Daya Bay have significant variation from other P.lutea population.The difference is smaller,as the latitude decreases.There is no genetic variation among low latitude populations.In addition,the SST fluctuation is more and more stable while the latitude decreases.Consequently,this study supposed that SST fluctuation in different latitude cause genetic variation in P.lutea.