Mice Inherit Gene Effects -- but Not Gene

May 27, 2006

mice27may27,1,1983646.story

Mice in a lab experiment inherited the effects of an aberrant gene

without inheriting the gene itself, a bizarre-sounding result that

may someday help scientists understand aspects of diabetes,

infertility and other problems.

Although DNA is the stuff of genes in mice and men, the study

indicates that DNA's chemical cousin, RNA, produced the result.

In this case the result was mice with white-tipped tails.

For the study, reported in Thursday's issue of the journal Nature,

scientists produced mice that carried one normal copy of a particular

gene and one aberrant copy.

When the mice were bred through several generations, researchers

found that 24 out of 27 mice that did not receive a copy of the

aberrant gene nonetheless showed the telltale white patches

associated with it.

When scientists bred these mice to others that had only normal copies

of the gene, most offspring with only normal gene copies still showed

the distinctive coloring. Experiments showed the trait could be

inherited through either the mother or father, and it went on for

generations in absence of the abnormal gene.

How can this be? Researchers focused on sperm, which are simpler to

analyze than eggs, and found evidence that RNA molecules there were

carrying the hereditary signal. For example, when RNA from mice

bearing the aberrant gene was injected into early embryos, about half

the resulting mice showed the distinctive tail.

RNA normally delivers instructions from genes to a cell's protein-

making machinery, so it makes sense that it might be involved in

transmitting a gene's effect. Just how it's operating in the mice is

not clear, said lead study author Minoo Rassoulzadegan of the

University of Nice, Sophia Antipolis, in France.

It's not clear how common or important this kind of inheritance is,

researchers said.

Recommended Posts