Optimizing Phylogenomics
A major problem in phylogenomics are loci that cannot reconstruct the correct gene tree either due to insufficient information content or poor alignment quality. RELEC genes maximize phylogenetic information content while maintaining presence and orthology across distant evolutionary scales.
What is a RELEC gene?
RELEC loci are single copy exons that are greater than 1,500 bases in length, have reasonable GC content, and are more rapidly evolving than RAG1 (a commonly used marker with strong phylogenetic utility). There is no unifying functional role of RELEC genes, but many of them are involved in binding and are expressed at low levels in all tissues.
Outperforming the Others
RELEC loci outperform Anchored Hybrid Enrichment and Ultraconserved Elements (two of the most common phylogenomic datasets) in all metrics, including phylogenetic informativeness, bootstrap support, alignment quality, and reduced gene tree estimation error.
Across Amniotes
RELEC loci are being used to resolve some of the most contentious and problematic nodes across terrestrial vertebrates. Several research groups are using RELEC for projects in birds, mammals, and reptiles. They can also be used in amphibians, but fewer are available. It is possible to build new RELEC-like datasets in any group.
The origin of Fiji's Iguanas
We recently applied RELEC to one of the most fascinating biogeographic questions: the origin of Fiji's Iguanas. The superior phylogenetic information content and clocklike evolution of RELEC genes allowed us to confidently resolve the Fiji Iguanas as the sister taxa of the North American Desert Iguanas with a divergence time just after the volcanic origins of Fiji. This and other fossil evidence supported one possiblity above all others: that iguanas rafted across the Pacific ocean from North America to Fiji. See our paper in PNAS for details.