Scientists find exception to Mendel's law

French scientists say they've found mice with a mutant gene can defy the laws of genetic inheritance -- passing on traits even if the gene is absent.

The scientists suggest RNA, a chemical cousin of DNA, passes on the characteristic to later generations, the BBC reported Thursday, but say more study is needed to confirm their conclusions.

The research involves a gene called Kit, which comes in two varieties: "normal" and "mutant." The mice inherit two Kit genes -- one from each parent -- and a mutant version gives them a spotty tail.

According to Mendel's laws of genetic inheritance, the combination of normal and mutant Kit genes should alone determine whether the mouse has a spotted or unspotted tail.

But scientists at the French Institute of Health and Medical Research in Paris and at the University of Nice-Sophia Antipolis found mice born with two normal versions of Kit also displayed variations caused by a mutant gene.

The study is detailed in the journal Nature.

Copyright 2006 by United Press International