ABSTRACT
From 1999-2001, West Nile virus (WNV) spread throughout the eastern United States (US) and was first detected in Georgia in 2001. To date, the virus has been detected in over 2,500 dead wild bird and mosquito samples from across Georgia. We sequenced the premembrane (preM) and envelope gene (E) (2004 bp) from 111 isolates collected from 2001 to 2011. To assess viral gene flow from other geographic regions in the US, we combined our data with WNV sequences available at the National Center for Biotechnology Information (NCBI) and performed phylogenetic analysis. We found evidence that WNV isolates detected in Chatham County Georgia most likely originated from the Northeastern United States. These results highlight the growing importance of adequate genetic surveillance for monitoring and controlling viruses of public health concern.
Subject(s)
Evolution, Molecular , RNA, Viral/genetics , West Nile Fever/veterinary , West Nile virus/classification , West Nile virus/isolation & purification , Animals , Birds/virology , Cluster Analysis , Culicidae/virology , Georgia/epidemiology , Molecular Epidemiology , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA , Sequence Homology , Viral Proteins/genetics , West Nile Fever/epidemiology , West Nile Fever/virology , West Nile virus/geneticsABSTRACT
We describe a new method of estimating the selfing rate (S) in a mixed mating population based on a population structure approach that accounts for possible intergenerational correlation in selfing rate, giving rise to an estimate of the upper limit for heritability of selfing rate (h2). A correlation between generations in selfing rate is shown to affect one- and two-locus probabilities of identity by descent. Conventional estimates of selfing rate based on a population structure approach are positively biased by intergenerational correlation in selfing. Multilocus genotypes of individuals are used to give maximum-likelihood estimates of S and h2 in the presence of scoring artifacts. Our multilocus estimation of selfing rate and its heritability (MESH) method was tested with simulated data for a range of conditions. Selfing rate estimates from MESH have low bias and root mean squared error, whereas estimates of the heritability of selfing rate have more uncertainty. Increasing the number of individuals in a sample helps to reduce bias and root mean squared error more than increasing the number of loci of sampled individuals. Improved estimates of selfing rate, as well as estimates of its heritability, can be obtained with this method, although a large number of loci and individuals are needed to achieve best results.
