Similarly, it is possible that the reduced DRA diversity observed in other taxa may be the result of multiple selective sweeps occurring independently across vertebrate lineages.
Multiple selective sweeps, simultaneously in progress, are characteristic of a well-mixed microbial population containing >10 cells (see, e.g., estimates in Appendix D ).
A. thaliana from northern Sweden show signs of multiple strong selective sweeps (Long et al., 2013) and harbors many polymorphisms that appear to be involved in local adaptation (specifically to minimum temperature; Hancock et al., 2011).
These simulations have considered several scenarios: one population with or without temporary division (Falush et al. 2006; Fraser et al. 2007, 2009), local genomic effects of NR (Vetsigian and Goldenfeld 2005), and multiple ecotypes with selective sweeps (Majewski and Cohan 1999b).
The divergence between engrailed haplotypes suggests an evolutionary history distorted by selection with multiple changes reflecting recurrent selective sweeps.
Moreover, there is evidence for positive selection and recent selective sweeps in antiviral RNAi genes from multiple Drosophila lineages, while homologous 'housekeeping' genes do not show this pattern [ 12,15,16].
Considering the genome as a whole and some limitations of these studies, extrapolation of our success on chromosome 2 genome-wide would suggest that many hundreds of sites will show multiple lines of evidence of selective sweeps.
The previous model is concerned with selective sweeps across multiple, ecologically distinct populations of prokaryotes, a situation similar to trans-specific selective sweeps in sexual eukaryotes [ 54].
We chose one gene (FOXP2) as a 'positive control' since previous studies had found evidence of selective sweeps (possibly multiple rounds) at this locus (25, 34, 35).
Essentially, with the spread of an advantageous mutation over multiple generations (a "selective sweep"), the particular allele at nearby genes that was associated with the original mutation also spreads.
In domestic chickens, genomic sequences from multiple lines reveal the presence of selective sweeps leading to the discovery of causative agents in growth differences between domestic lines [ 8].
