When a Gene Makes You Smell Like a Fish: And Other Amazing Tales about the Genes in Your Body by Lisa Seachrist Chiu
This is a rather technical book on human genetics. Recent research is described, with plenty of names of researchers and institutions of research. A background in college biology would be helpful for understanding most of the material. It is mainly about diseases that are caused by defective genes, including:
- Metabolic diseases that cause smelly or colored chemicals to be excreted in urine and sweat,
- Wilson’s disease, which involves copper metabolism,
- Marfan Syndrome, which affected one of my favorite actors, Vincent Schiavelli, (4) Huntington’s Disease, which runs in families,
- Fragile X Syndrome, which causes mental retardation,
- the blood-clotting disease hemophilia, and
- male-pattern baldness.
Some genetic diseases more common among some ethnic groups, such as Amish cerebral palsy, Mennonite maple syrup urine disease, and Celtic hereditary hemochromatosis.
The author also discusses epigenetics, which is about whether a gene is turned on or off. Since females have two X chromosomes and men only one, in females one of the two X chromosomes is turned off, so males and females will produce equal amounts of the gene’s protein product. However, which of the two X chromosomes is turned off, the one from the woman’s mother, or the one from the woman’s father, varies from cell to cell in the body. Thus all females are chimeras. This mechanism also gives rise to calico cats.
Recombination Activating Genes
The author mentions the recently discovered recombination activating genes (RAG1 and RAG2), that are involved in creating a wide diversity in the antigen-binding specificity of antibodies and cellular adaptive immunity. It appears that they were transferred from a virus or a bacteria by horizontal evolution to a primitive fish millions of years ago.
The Japanese people are a combination of the original Jomon inhabitants of the islands and Korean immigrants called Yayoi. The Ainu of Hokkaido are similar to the Jomon. The inhabitants of Honshu, Shikoku and Kyushu are more similar to the Koreans. The author claims that the Japanese language is an isolate, but the physiologist Jared Diamond and some linguists have written elsewhere that Korean and Japanese have a common ancestor.
Lactose intolerance is the rule for most peoples of the world. When children grow up, they generally stop making the enzyme for digesting the milk sugar lactose. However, some peoples, such as northern Europeans, have developed a tolerance for milk into adulthood. It appears to have evolved among a cattle-herding people, the Udmerts (Votyak), who lived between the Ural mountains and the Volga river several thousand years ago. Drinking cow milk by adults and lactose tolerance then spread to Europe.