Zea mays

Meiotic crossover (CO) landscape differs inter- and intra-species, as well as between sexes. Here, the authors show that male meiosis produces more COs than female in maize and detect CO maturation inefficiency in some genetic backgrounds, which may help to improve breeding efficiency.

In this Review, the author discusses current knowledge on the paramutations that occur in maize and contrasts these behaviours with potentially parallel examples in metazoans. He highlights the key role of small RNAs (sRNAs) in diverse paramutation mechanisms across eukaryotes and considers the evolutionary importance of these regulatory systems.

Jinsheng Lai and colleagues report the resequencing of 278 inbred maize lines and perform a genome-wide analysis of genetic changes during modern breeding. Using SNP imputation, the authors also perform a genome-wide association study for cob color, silk color and date to anthesis. The authors identified association signals with significant P values near known targets.

The nucleotide diversity present in maize exceeds that in humans by an order of magnitude, and it has been challenging to characterize the high levels of diversity in this important crop. Doreen Ware and colleagues have identified 55 million SNPs in 103 domesticated and pre-domestication Zea mays varieties, as well as in a representative from the sister genus Tripsacum.