Tall Genes

We knew that height was hereditary, but now scientists have identified exactly a gene which helps in determin how tall we will be. Each copy of the tall allele adds approximately one-fifth of an inch. An allele, in case you were wondering, is any one of a number of possible DNA codings that occupies a given position on a chromosome. Studies suggest that 90 percent of height is genetic, so the researchers are expecting to find many more height genes.

So what does identifying such a gene or allele do for us? Well, there is the case for general knowledge and understanding of how the human genome works, but for others it may be for the benefit of embryo eugenics. William Saletan of Slate magazine keeps his eye on the topic and writes on it periodically. He explains that of the 3 million children born via in vitro fertilization thousands go through preimplantation genetic diagnosis, a technique for weeding out flawed embryos. Saletan asks,

"What flaws are we screening for? That's the most uncomfortable question of all. Sometimes the flaw is a horrible disease. But increasingly, it's a milder disease, the absence of useful tissue, or just the wrong sex. If you think it's hard to explain where babies come from, try explaining where baby-making is going."