Genomic islands are hotspots for horizontal gene transfer (HGT) in bacteria, but, for Prochlorococcus, an abundant marine cyanobacterium, how these islands form has puzzled scientists. With the discovery of tycheposons, a new family of transposons, Hackl et al. provide evidence for elegant new mechanisms of gene rearrangement and transfer among Prochlorococcus and bacteria more broadly.

Species and populations may adapt to climate change by microevolutionary processes. However, standing genetic variation can be insufficient for this to occur. An interesting new study of a system of rainbowfish species shows that intraspecific hybridization enriches gene pools with adaptive variation that may allow persistence in a changing climate.

Gigantism is prevalent in animals, but it has never reached more extreme levels than in aquatic mammals such as whales, dolphins, and porpoises. A new study by Silva et al. has uncovered five genes underlying this gigantism, a phenotype with important connections to aging and cancer suppression in long-lived animals.

The burden of human diseases is dominated by complex, polygenic disease rather than by monogenic disorders associated with single, highly penetrant, genetic mutations. Since the mid-2000s, GWAS have been the preferred tool for identifying associations between genetic variants and complex traits [1]. While the association between genomic variation and phenotype has long been understood, GWAS have…

Organelle DNAs (orgDNAs) in mitochondria and plastids are generally inherited from the maternal parent; however, it is unclear how their inheritance mode is controlled, particularly in the plastids of seed plants. Chung et al. identify two factors that affect maternal inheritance in tobacco plastids: cold temperature and DNA amount in pollen.

REs comprise approximately half of the genome, with classes of REs including TEs (see Glossary), satellite DNA, rDNA, and segmental duplications [1]. Until recently, REs were mostly ignored due to: (i) their repetitive nature, which complicates sequencing; and (ii) the widespread perception that REs were ‘junk’ DNA [2]. Advances in sequencing technology and computational analysis of repetitive…

Understanding a remarkable event at the start of life, the oocyte-to-embryo transition (OET), has remained elusive, especially in humans. Using newly developed techniques, Liu et al. showed that human maternal mRNAs undergo global poly(A) tail-mediated remodeling during OET, identified the enzymes involved, and demonstrated the essentiality of remodeling for embryo cleavage.