Understanding Genetics: Human Health and the Genome

Many people have trouble believing that chromosome number can change and stay changed in a species. Their first thought is often of Down syndrome or the other problems that usually come with missing or extra chromosomes. It can be hard to imagine how a living thing could end up with a new chromosome number without these problems. And yet it happens all the time in creatures as varied as yeast, corn, butterflies, voles and even mice. And now it has been seen in people. viaUnderstanding Genetics: Human Health and the Genome.