什么是提前终止密码子，它的特点和主要作用是什么？

应该是某个基因发生了突变，导致终止密码子提前出现。它会导致产生的蛋白不完全等，从而丧失原来基因的功能！

看来这篇文章是讲不同水稻品种间的SNP差异，图中的意思应该是有些SNP的出现导致了终止密码子提前出现（也就是所谓的Nonsense mutation）

From Wikipedia：

In genetics, a nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and in a truncated, incomplete, and usually nonfunctional protein product. It differs from a missense mutation, which is a point mutation where a single nucleotide is changed to cause substitution of a different amino acid.

主要作用：
1 Nonsense-mediated mRNA decay

Despite an expected tendency for premature termination codons to yield shortened polypeptide products, in fact the formation of truncated proteins does not occur often in vivo. Many organisms—including humans and lower species, such as yeast -- employ a nonsense-mediated mRNA decay pathway, which degrades mRNAs containing nonsense mutations before they are translated into nonfunctional polypeptides

2 Pathology associated with nonsense mutations

Nonsense mutations can cause a genetic disease by damaging a gene responsible for a specific protein, for example, dystrophin in Duchenne muscular dystrophy.

"提前终止密码子"没有这个东西,是不是搞错了.
是不是说基因突变后,使mRNA中提前出现了终止密码子啊.