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More Grammar Rules

In the 1950s, Erwin Chargaff noted that the amount of adenine in a given stretch of DNA is equal to the amount of thymine, and guanine to cytosine, a finding that James Watson and Francis Crick used to support their double-helix model of DNA. At arXiv, two biophysicists report that they've extended these "grammar" rules for DNA. "Chargaff's rules apply to words where k=1, in other words, to single nucleotides," says The Physics arXiv Blog. "But what of words with k=2 (eg AA, AC, AG, AT and so on) or k=3 (AAA, AAG, AAC, AAT and so on)?" Brazil's Michel Beleza Yamagishi and Roberto Herai searched through large genomic data sets from more than 30 species, finding a fractal-like pattern, arXiv adds. "To the best of our knowledge, these new rules show for the first time that oligonucleotide frequencies do have invariant properties across a large set of genomes, and these rules, regardless the number of nucleotides remains the same (self-similarity)," the researchers write in their paper.

The researchers add that their work has a practical application: It could be used to check short read data for biases.

The Scan

Self-Reported Hearing Loss in Older Adults Begins Very Early in Life, Study Says

A JAMA Otolaryngology — Head & Neck Surgery study says polygenic risk scores associated with hearing loss in older adults is also associated with hearing decline in younger groups.

Genome-Wide Analysis Sheds Light on Genetics of ADHD

A genome-wide association study meta-analysis of attention-deficit hyperactivity disorder appearing in Nature Genetics links 76 genes to risk of having the disorder.

MicroRNA Cotargeting Linked to Lupus

A mouse-based study appearing in BMC Biology implicates two microRNAs with overlapping target sites in lupus.

Enzyme Involved in Lipid Metabolism Linked to Mutational Signatures

In Nature Genetics, a Wellcome Sanger Institute-led team found that APOBEC1 may contribute to the development of the SBS2 and SBS13 mutational signatures in the small intestine.