In “Re-Write The Textbooks: Key Genetic Phenomenon Shown To Be Different Than Believed,” (ScienceDaily, July 2, 2009) we learn,
Because females carry two copies of the X chromosome to males’ one X and one Y, they harbor a potentially toxic double dose of the over 1000 genes that reside on the X chromosome.
To compensate for this imbalance, mammals such as mice and humans shut down one entire X-chromosome through a phenomenon known as X-inactivation. For almost two decades, researchers have believed that one particular gene, called Xist, provides the molecular trigger of X-inactivation.
Now, a new UNC study appearing online July 1 in the journal Nature disputes the current dogma by showing that this process can occur even in the absence of this gene.
Hope no careers went down on account of doubt on this point …