Blogging the Human Genome: Elizabeth Taylor’s double eyelashes. - Slate Magazine
Scientists refer to DNA that appears in the same basic form in many, many species as highly “conserved” because creatures remain very conservative about changing it. (Some hox and hox-like genes are so conserved that scientists can rip them out of chickens, mice, and flies and swap them between species, and the genes more or less function the same.)
Perhaps the most important transcription factors are hox genes, which steer bodily development from our earliest hours. Insects, fish, mammals, reptiles, and all other animals share these genes, and the ubiquity of hox in the animal kingdom explains why most animals have the same basic body plan: a cylindrical trunk with a mouth at one end, an anus at the other, and various appendages sprouting in between.
Human beings have something like 23,000 DNA genes
No one kept it a secret exactly during her lifetime, but few people knew that Elizabeth Taylor was a mutant. In fact her condition, distichiasis, which usually involves a frameshift mutation near the tip of chromosome 16, helped accent Taylor’s famously lovely eyes with an extra-sexy set of double eyelashes to bat at the cameras. Taylor lucked out, though: In other victims, distichiasis scars the corneas, swells the limbs grotesquely, opens up cleft palates, and causes varicose veins. In 7 percent of patients, it also leads to heart disease, and perhaps not coincidentally, Taylor had a history of heart trouble and died of heart failure in March 2011.
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