The journey from maize to corn isn鈥檛 just about going from farm to table. It starts with an evolutionary event that has puzzled plant biologists for decades. This week At the Lab, CSHL Professor, HHMI Investigator, and Genetics Society Medal recipient Rob Martienssen unravels a 4,000-year-old mystery in just over three minutes.
Read the related story: Corn鈥檚 鈥榤issing link鈥�
Transcript
Nick Fiore: You鈥檙e now At the Lab with 黑料吃瓜资源. My name is Nick Fiore, and this week At the Lab, 鈥淗ow maize became corn.鈥�
NF: Corn starch, corn syrup, cornmeal, cornbread, cornflakes, and good old-fashioned corn on the cob. Nowadays, corn is everywhere you look. But how did it get here?
NF: I don鈥檛 mean 鈥渉ere鈥� as in the kitchen table. This question is much bigger. It goes back millennia. Here鈥檚 CSHL Professor Rob Martienssen.
Rob Martienssen: What we think of now as maize was domesticated from teosinte parviglumis, a wild grass in the lowlands of Mexico, about 9,000 years ago. However, domesticated maize was confined to that area for climatic reasons for the next 5,000 years until it hybridized with another wild teosinte called teosinte mexicana, which could grow in much colder and dryer climates. And that hybridization is thought to have been responsible for the remarkably rapid dispersal of maize throughout the Americas.
NF: Plant biologists like Martienssen have known this much for decades. The real question was how did maize adopt the traits needed to spread so widely so quickly? Now, with the help of Jerry Kermicle, a corn whiz from the University of Wisconsin, and Ben Berube, a CSHL grad student, Martienssen may have an answer.
RM: Something called selfish inheritance or gene drive, where a gene becomes preferentially inherited because it kills the other, in this case, pollen grains that don鈥檛 carry that gene. Gene drive is one way in which you can get an awful lot of genes into a hybrid in such a way that it鈥檚 forced into the next generations. And if you鈥檙e lucky, that will carry along with it traits that are very useful.
NF: What鈥檚 remarkable about this instance of gene drive is that it involves a particular group of molecules known as small RNAs.
RM: Even more remarkable, animal genomes have something similar going on in fruit flies. And there鈥檚 even an example in mouse.
NF: Small RNAs are also quite common in human sperm cells. So, one question now is could similarly selfish inheritance help explain the sudden jump from Neanderthals to homo sapiens? In other words, could a gene drive be the missing link? It might sound crazy, but when it comes to maize and corn, we now think the answer is yes.
NF: Thanks again for joining us At the Lab. If you like what you heard, please subscribe wherever you get your podcasts and visit us online at CSHL.edu. For 黑料吃瓜资源, I鈥檓 Nick Fiore, and I鈥檒l see you next time At the Lab.