In this week's Nature, two separate Max Planck-led research groups report the genomes of two organisms that are capable of regrowing body partners, providing insights into the genetics of regeneration. In the first study, researchers describe the sequencing and assembly of the 32-gigabase-pair genome of the Mexican axolotl, Ambystoma mexicanum, identifying genes and microRNA sequences whose expression is highly enriched in the cells of regenerating limbs, and noting the absence of a gene essential for development in a number of other animals. In the second study, investigators find the much smaller genome of the planarian flatworm, Schmidtea mediterranea, to be lacking a number of highly conserved and essential genes including ones related to DNA repair and cell division. In their studies, both groups of investigators took advantage of a new algorithm that, combined with long-read sequencing, helped improve genome assembly. GenomeWeb has more on this, here.
In Nature Genetics, a multi-institute team of researchers presents a genome-wide analysis of multi-drug resistant Mycobacterium tuberculosis, characterizing the genetic determinants of treatment resistance. They performed a genome-wide association study of nearly 6,500 M. tuberculosis clinical isolates from more than 30 different countries, followed by a phylogenetics-based test for independent mutations. Among their findings were novel mutations for resistance to three key tuberculosis drugs and new epistatic relationships between candidate drug resistance-associated genes. "Findings from this study will inform the design of new diagnostic tests and expedite the investigation of resistance and compensatory epistatic mechanisms," the authors state. GenomeWeb also covers this paper, here.
Also in Nature Genetics, University of Kentucky researchers and collaborators publish a new genomic assembly of the sea lamprey, Petromyzon marinus. An analysis of the assembly revealed chromosomal and whole-genome duplications with significant roles in the evolution of ancestral vertebrate and lamprey genomes, as well as several hundred genes that are reproducibly eliminated from somatic cells during early development in lamprey. The authors expect the new assembly to improve the ability to use the lamprey as a comparative evolutionary model.