We report a modified microsatellite enrichment technique that was used to isolate tetranucleotide (AAAG) repeat loci from a group living Australian lizard, Egernia stokesii. The enrichment method is based on magnetic/biotin capture of repetitive sequences from restricted genomic DNA. The technique can be performed rapidly and recovers microsatellite loci with both flanking sequences intact. Twenty unique microsatellite loci (16.7% of white colonies screened) containing 10 or more tetranucleotide repeats were identified. Eleven loci were further analyzed in 10 unrelated individuals and had heterozygosities ranging from 0 to 90%. These loci will be used to investigate genetic relationships within and among crevice homesites of E. stokesii and also genetic differentiation among E. stokesii populations. At least four of the microsatellite loci can be amplified in related taxa, including other Egernia species and the closely related genera Corucia, Cyclodomorphus, and Tiliqua.

In higher organisms such as vertebrates, it is generally believed that lateral transfer of genetic information does not readily occur, with the exception of retroviral infection. However, horizontal transfer (HT) of protein coding repetitive elements is the simplest way to explain the patchy distribution of BovB, a long interspersed element (LINE) about 3.2 kb long, that has been found in ruminants, marsupials, squamates, monotremes, and African mammals. BovB sequences are a major component of some of these genomes. Here we show that HT of BovB is significantly more widespread than believed, and we demonstrate the existence of two plausible arthropod vectors, specifically reptile ticks. A phylogenetic tree built from BovB sequences from species in all of these groups does not conform to expected evolutionary relationships of the species, and our analysis indicates that at least nine HT events are required to explain the observed topology. Our results provide compelling evidence for HT of genetic material that has transformed vertebrate genomes.