Part IV -Transposable Element Emily looked down at her worksheet and said. \"So
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Question
Part IV -Transposable Element Emily looked down at her worksheet and said. "So domestication caused the expression of the branching gene to rise, right? Professor Griffin leaned back in the chair and said. "To answer this question, we first need to know what is different berween maize and teosinte rb.1. A small piece of DNA called the transposable element is present near the tbl gene in maize, but not in teosinte. The insertion of this transposable element is responsible for the increased tbl expression in maize. What makes it interesting is that this insertion can be dated to around 10.000 years prior to maize domestication. Emily's cyes widened. "Oh. I know, chis means that Question . Finish Emily's sentence for her in the space below. Did domestication cause the expression of the branching gene to riseExplanation / Answer
In seeking to better understand how teosinte gave rise to corn, a scientific team has pinpointed one of the key genetic changes that paved the way for corn’s domestication. a major change occurred about 23,000 years ago, when a small piece of DNA — a jumping gene known as Hopscotch — inserted itself into the control region of a teosinte gene that affects plant architecture. This case is among the first to show that a jumping gene can cause alterations in gene expression that impact evolution.
“Hopscotch cranked up the gene’s expression, which helped the plant produce larger ears with more kernels, plus become less branchy, and so those early farmers picked plants with the Hopscotch to breed,” Jumping genes are strange genetic entities. Found in all sorts of organisms, these pieces of DNA, which carry just a few genes, have the ability to splice themselves out of their current position in the genome and “jump” to other spots. As they mix and mingle with the genome, jumping genes, which are also known as transposable elements, create genetic variation that evolution can act upon. Typically, jumping genes’ effects are neutral or bad, as when they land in a stretch of junk DNA or disrupt a critical gene.In corn, Hopscotch dials up expression of the teosinte branched 1 (tb1) gene, which produces a transcriptional regulator protein that represses branching, encouraging the plant to grow a single stalk and produce larger ears with more kernels. When early Mexican farmers first encountered teosinte with this Hopscotch insertion, the rare plants must have been prized breeding stock: Today 95 percent of modern corn has this particular genetic alteration.