30 July 2006

All in the genes?


Two startling things can be said about the picture to the right, which shows two generations of a high pedigree race horse.

First, notice that there is no genetic father. Smart Little Lena stands alone as the genetic forbearer. The five horses pictured beneath Smart Little Lena are her clones, produced by surrogate mothers. That is startling enough, because it has been a long hard road to producing substantial numbers of horse offspring from adult somatic cells.

But there is something else that I hope has not escaped your attention. Ask yourself: do any of these kiddies look like their mother? (it might have helped if they had used a baby photo of Smart Little Lena ;-).

The clones don't even look like each other.

But don't go rushing to the conclusion that I am breaking a scandal about faked clones. These are clones, alright. Their obvious differences arise from what are broadly called "epigenetic factors". This is a nice neat term for a host of poorly understood mechanisms that affect how the genetic code, which is identical in all 6 horses shown, is translated into a living, breathing, animal.

The picture shows the state of the art in horse cloning. The situation would, in all likelihood, be the same for humans. Serious ethical questions aside, would anybody want to clone themselves under these circumstances? No matter what you look like, your cloned offspring could turn out looking just a little bit like Alex, Bogy, Camby, Dave and Eli.

Source: Publication by Stephanie L. Church, Nature Biotechnology 24, 605 - 607 (2006)