>>The evolution of corn (maize) is a fascinating story. For a long time, scientists couldnt figure out where domesticated corn originally came from — it doesnt look like anything that grows in the wild. It took serious sleuthing by geneticists, botanists, and archaeologists to figure out that maize split off from teosinte grass some 9,000 years ago. (The two are surprisingly similar at the DNA level, differing by just a handful of genes.) As maize became domesticated in Mesoamerica, it was radically altered through selective breeding. Early farmers would examine their plants and save the seeds of those that were larger, or tastier, or whose kernels were easier to grind. By 4,000 BC, cobs were already an inch long. Within just a few thousands years, cobs had grown to many times that size. Later on, plant hybridization became an important breeding method to further cultivate certain traits. Nowadays, corn is grown all over the planet, and humans are still making changes using more advanced breeding techniques. In the 1980s, for instance, seed companies turned to genetic engineering — so, for instance, scientists inserted genes from Bt soil bacteria into corn to help the plant ward off pests. And some researchers are hoping to develop corn varieties that can withstand drought.
Posted on: Sat, 18 Oct 2014 06:40:28 +0000