In this week's Nature, two independent research groups report using CRISPR-Cas9 genome editing to generate new strains of the yeast Saccharomyces cerevisiae with far fewer chromosomes than normal. In the first study, a team of Chinese scientists fuse S. cerevisiae's 16 chromosomes into one, while in the second study, a group led by NYU Langone Health investigators fuses the yeast's chromosomes to only two. While in both cases the fusion alters 3D chromosomal structure significantly, the new strains remain robust and capable of survival. However, these strains also display reproduction disadvantages versus wild-type yeast, suggesting a competitive benefit to multiple chromosomes. GenomeWeb has more on this, here.
In Nature Genetics, an international group of scientists describe using short-read sequencing to sequence and de novo assemble the genome for maize W22 inbred, a strain of corn widely used as a platform for studying the plant's genetics. The team finds significant structural heterogeneity between their genome and an existing reference genome at multiple scales, and uses a combination of technologies to map open reading frames, open chromatin sites, and DNA methylation profiles. "The resources developed here integrate W22 as a community reference genome for functional genomics and provide a foundation for the maize pan-genome," the investigators write.
Also in Nature Genetics, a group of researchers from industry and academia presents a large-scale genetic study of atrial fibrillation (AF), revealing a number of new genome-wide risk variants for the heart condition. The collaborators perform a genome-wide association study of more than one million people, including 60,620 atrial fibrillation cases and 970,216 controls, and find 142 independent risk variants at 111 loci. They also pinpoint 151 functional candidate genes likely to be involved in AF — many of which near genes linked to heart defects or muscle function. Pathway and functional enrichment analyses, meanwhile, highlight fetal heart tissue and pathways related to cardiac development as important for developing AF. GenomeWeb also covers this study, here.