Victorian rule of thumb beats genetic prediction

A rule of thumb from the 1800s to predict the height of children based on their parents stature is still far more accurate than the best genomic predictions. In 1886 Sir Francis Galton a Victorian scientist who also pioneered the field of eugenics published a technique to predict the height of children. It averages the height of both parents and makes adjustments for age and sex.

"It s really not rocket science " says Yurii Aulchenko a geneticist at Erasmus University Medical Center in Rotterdam in the Netherlands. Aulchenko s team compared this approach to a more complicated calculation based on gene variations linked to height. Researchers previously identified these mutations by scanning the genomes of tens of thousands of people and then hunting for single letter changes shared by people of similar stature. Minor correlation Aulchenko s team analysed 54 of these genetic variants across 5748 Dutch people and calculated a simple score for each person. The higher a person s score the more gene variants linked to tall stature he or she possessed. But when these numbers were plotted against each person s height and adjusted for age and sex Aulchenko s team found only a minor correlation between a person s genetic score and their actual height. Galton s method on the other hand proved about 10 times better at guessing the height of another 550 people.

Joel Hirschhorn a geneticist at the Broad Institute of Massachusetts Institute of Technology and Harvard University in Cambridge Massachusetts isn t surprised by the poor prognostic ability of genes linked to height – including a handful identified by his lab. The team noted just as much when it published its findings in 2008. This is because most genetic variations have a miniscule affect on height and many more have yet to be identified Aulchenko says. A few traits such as eye colour are easier to predict with genes and new research will certainly improve genetic prognostication. But for now most of our features remain a genetic black box.

via Victorian rule of thumb beats genetic prediction - science-in-society - 03 March 2009 - New Scientist.

Try these sites if you want to predict your child's height:

While there is no magic way to look into the future to see how tall your children will be when they grow up, these height predictors can give you a pretty good idea of what your child's future height will be:

• Kid's Height Predictor - predict your children's future height based on their genetic potential (which is based on their parents' midparental height)


• Kid's Height Calculator - Two Years Times Two Method, which uses simple linear regressions and doubles a child's height at age two years


• Yet Another Height Calculator - use your child's current height and where they are on the growth curve right now to predict their future height