Ancestry of the two subgenomes of maize

Abstract

Maize (Zea mays ssp. mays) is not only one of the world's most important crops, but it also is a powerful tool for studies of genetics, genomics, and cytology. The genome of maize shows the unmistakable signature of an ancient hybridization event followed by whole genome duplication (allopolyploidy), but the parents of this event have been a mystery for over a century, since studies of maize cytogenetics began. Here we show that the whole genome duplication event preceded the divergence of the entire genus Zea and its sister genus Tripsacum. One genome was donated, in whole or in part, by a plant related to the modern African genera Urelytrum and Vossia, although genomic rearrangement has been extensive. The other genome donor is less well-supported, but may have been related to the modern Rottboellia-Hemarthria clade, which is also African. Thus Zea and Tripsacum together represent a New World radiation derived from African ancestors.

Parallels between natural selection in the cold‐adapted crop‐wild relative Tripsacum dactyloides and artificial selection in temperate adapted maize

“…The common ancestor of Zea and Tripsacum is predicted to have been adapted to tropical latitudes (Doebley, ; Edwards and Smith, ; McKain et al ., ). Therefore, the study of how natural selection adapted T. dactyloides to temperate climates represents an informative parallel to the adaptation of maize to temperate climates through artificial selection.…”

Tissue-specific gene expression and protein abundance patterns are associated with fractionation bias in maize

“…A recent study suggests a common evolutionary relationship between maize and current day Urelytrum/Vossia which may provide clues to the nature of the parents of the allopolyploidy event that followed the speciation of ancestral maize and ancestral sorghum [26]. It has been suggested that these parents could be linked to the modern subgenomes in maize such that the origins of the subgenomes could be revealed, however for the purposes of this study we continue to use the definitions of Maize1 and Maize2 referred to in Schnable et al [15].…”

Why I Tweet

“…Longer than a title, shorter than an abstract, and often including an important figure, you can get the gist of a lot of publications in short order. As an example, I can't honestly say that I would find or read the taxonomic literature these days, but a taxonomic researcher tweeted about his pre‐print publication identifying an obscure African grass as the ancestral relative of teosinte (predecessor of maize, Zea ) before the genome duplication (McKain et al, 2018); I was able to have a conversation and learn that it has not been studied in the U.S., is perennial, etc.—none of which was in his publication, yet directly relevant to my interest developing perennial maize.…”