If you knew the complete genome sequence of someone could you tell where they came from and their ethnic background (race)? The answer is confusing according to Siddhartha Mukherjee writing in his latest book "The Gene: an intimate history." The answer appears to be "yes" but then Mukherjee denies that knowing where someone came from tells us anything about their genome or their phenotype. He writes the following on page 342.
... the genetic diversity within any racial group dominates the diversity between racial groups. This degree of intraracial variability makes "race" a poor surrogate for nearly any feature: in a genetic sense, an African man from Nigeria is so "different" from another man from Namibia that it makes little sense the lump them into the same category.
For race and genetics, then, the genome is strictly a one-way street. You can use the genome to predict where X or Y came from. But knowing where A or B came from, you can predict little about the person's genome. Or: every genome carries a signature of an individual's ancestry—but an individual's racial ancestry predicts little about the person's genome. You can sequence DNA from an African-American man and conclude that his ancestors came from Sierra Leone or Nigeria. But if you encounter a man whose great-grandparents came from Nigeria or Sierra Leone, you can say little about the features of this particular man. The geneticist goes home happy; the racist returns empty-handed.
I find this view very strange. Imagine that you were an anthropologist who was an expert on humans and human evolution. Imagine you were told that there's a woman in the next room whose eight great-grandparents all came from Japan. According to Mukherjee, such a scientist could not predict anything about the features of that woman. Does that make any sense?
I suspect this is just a convoluted way of reconciling science with political correctness.
Many ethnic groups carry distinct signatures. For example, from a genome sequence you can usually tell if an individual is African-American, Caucasian, Asian, Satnami, or Ashkenazi Jew, even if you've never laid eyes on the patient. A well-regarded research scientist whom I had never met made his genome sequence publically available as part of a research study. I remember scrolling through his genetic variant files and trying, more successfully than I had expected, to guess what he would look like before I peeked at his webpage photo. The personal genome is more than skin deep.
This makes more sense to me. If you know what you look for—and Simon Monroe certainly does—then many of the features of a particular person can be deduced from their genome sequence. And if you know which variants are more common in certain ethnic groups then you can certainly predict what a person might look like just by knowing where their ancestors came from.
What's wrong with that?
