2.5 Conclusion

We propose that paralog genes generated by tandem duplication start their life coregulated within TADs, then are moved outside to other places in the chromosome and eventually to different chromosomes. TADs would then fit genomic duplications situating the new copy in a duplicated regulatory enviroment. Subsequent genomic rearrangements would create divergent regulatory circuits eventually allowing their disentanglement. An exception would be genes that precise to be strongly co-regulated with the original copy, for example, to produce a replacement protein.

TADs would thus act as protective nests for evolving newcomer genes. This seems to be a reasonable evolutionary mechanism, much simpler than creating from nothing a complete new regulatory environment for a new gene.