RT Journal
A1 Koch, Romke
A1 van Luenen, Henri G.A.M.
A1 van der Horst, Marieke
A1 Thijssen, Karen L.
A1 Plasterk, Ronald H.A.
T1 Single Nucleotide Polymorphisms in Wild Isolates of Caenorhabditis elegans

JF Genome Research 
JO Genome Research 
YR 2000 
FD November 01 
VO 10 
IS 11 
SP 1690 
OP 1696 
DO 10.1101/gr.GR-1471R 
UL http://genome.cshlp.org/content/10/11/1690.abstract 
AB 
Caenorhabditis elegans (isolate N2 from Bristol, UK) is the first animal of which the complete genome sequence was available. We sampled genomic DNA of natural isolates of C. elegans from four different locations (Australia, Germany, California, and Wisconsin) and found single nucleotide polymorphisms (SNPs) by comparing with the Bristol strain. SNPs are under-represented in coding regions, and many were found to be third base silent codon mutations. We tested 19 additional natural isolates for the presence and distribution of SNPs originally found in one of the four strains. Most SNPs are present in isolates from around the globe and thus are older than the latest contact between these strains. An exception is formed by an isolate from an island (Hawaii) that contains many unique SNPs, absent in the tested isolates from the rest of the world. It has been noticed previously that conserved genes (as defined by homology to genes in Saccharomyces cerevisiae) cluster in the chromosome centers. We found that the SNP frequency outside these regions is 4.5 times higher, supporting the notion of a higher rate of evolution of genes on the chromosome arms.