During the process of fertilization, paternal genome exchange protamines and DNA demethylation and histone modifications occur (Santos et al. 2002).
In all, 35 reports have so far emerged from this avian genome sequence collection, and provide rich new genomic details about avian reproduction, sex determination, sexual adaptations, behaviors, endogenous retroviral footprints, genome contraction relative to reptiles and mammals, genome exchange breakpoints and ecological accommodations.
PeSL-mediated recombination allows for targeted genome exchanges between phages containing the conserved PeSL elements (acting as linker sequences) and allows for the insertion/deletion of endogenously expressed modules without disrupting neighboring gene regulation (due to their terminators).
In viruses, genetic exchange takes the form of recombination [ 4], when information from two template strands is incorporated to a daughter strand, or reassortment [ 5], in which viruses with segmented genomes exchange chromosomes.
The need to go beyond phylogeny is emphasized by the extent of horizontal gene transfer (HGT), with portions of genomes exchanged across different species [12].
In the AT genome, some exchanges occurred between Ga10 and Ga12 and this phenomenon as observed in previous studies.
Despite having a mechanism to maintain the integrity of their split genomes, component exchange, referred to as pseudo-recombination for begomoviruses, does occur [ 13- 16].
Horizontal or lateral transfer of genetic material between distantly related prokaryotes has been shown to play a major role in the evolution of bacterial and archaeal genomes, but exchange of genes between prokaryotes and eukaryotes is not as well understood.
Streptomyces pratensis has high rates of homologous recombination but the impact of such gene exchange on genome evolution and the evolution of natural product gene clusters remains uncharacterized.
However, patterns of introgression appear heterogeneous across the genome, since the exchange of genomic regions between species depends greatly on their fitness effects or the fitness effects of linked regions [ 3].
The construction of recombinant genomes by exchanging genes or even introducing new genes is now commonplace in virology, and, indeed, some of the prospects for such engineering are worrying (e.g., Jackson et al. 2001) or involve exchanging genes from highly virulent human pathogens (Twu et al. 2007).
