Phylogenetic investigation of human FGFR-bearing paralogons favors piecemeal duplication theory of vertebrate genome evolution

- This study dissects evolutionary mechanisms that created fourfold paralogous regions on human chromosomes 4/5/8/10.
- Duplication history of 21 human gene-families by employing protein sequence data from an expanding range of animal species.
- Results demonstrate that human FGFR-bearing paralogons evolved by small-scale regional duplication events.
- Regional duplication events recovered in this study occurred at widely different time points in animal history.
- Together with our previous results, these data reject the assumption that ancestral vertebrate genome was shaped by WGDs.

BackgroundUnderstanding the genetic mechanisms underlying the organismal complexity and origin of novelties during vertebrate history is one of the central goals of evolutionary biology. Ohno (1970) was the first to postulate that whole genome duplications (WGD) have played a vital role in the evolution of new gene functions: permitting an increase in morphological, physiological and anatomical complexity during early vertebrate history.ResultsHere, we analyze the evolutionary history of human FGFR-bearing paralogon (human autosome 4/5/8/10) by the phylogenetic analysis of multigene families with triplicate and quadruplicate distribution on these chromosomes. Our results categorized the histories of 21 families into discrete co-duplicated groups. Genes of a particular co-duplicated group exhibit identical evolutionary history and have duplicated in concert with each other, whereas genes belonging to different groups have dissimilar histories and have not duplicated concurrently.ConclusionTaken together with our previously published data, we submit that there is sufficient empirical evidence to disprove the 1R/2R hypothesis and to support the general prediction that vertebrate genome evolved by relatively small-scale, regional duplication events that spread across the history of life.