Friday, January 21, 2011

Recent Ancestry-Deep Ancestry

When asked, "What is your ancestry?" most people think back to their great grandparents and the countries of their origin(for me personally it is Swedish, Croatian(Dalmatia), Norwegian, and Scottish). But when considering life on an evolutionary timescale what I can hold in my own memory or gather from relatives is functionally similar to the memory of a baby.

A baby has difficulty learning complex things because it has many organs and brain functions that have yet to be developed and if it had to remember what happened 10 days ago in order to make a decision today it wouldn't do very well. Our ancestral memory though has recently undergone exponential growth. Due to advances in the field of genetics we can now trace our own personal history back thousands of years. How can we use this knowledge?

The second area I'd like to delve into is a way of testing for adaptability to various foods and begin to develop adaptability ratings based on these regions

N. Europe
S. Europe
N. Africa
S. Africa
N. America
S. America
C. Asia
E. Asia
S. Asia

Specifically you would place yourself in one of these categories not by appearance of ancestry, but by DNA markers of ancestry as outlined in human Genographic project. The genographic project is a privately-funded, not-for-profit collaboration between the National Geographic Society, IBM and the Waitt Family Foundation dedicated to mapping humanity's route out of Africa, starting with the initial suspected population in southern Africa 60,000-40,000 years ago all the way up to the present day. Here's a map of a few of the critical population points.

Each of the points refers to a gene marker, taken from section of each participants. There are, parts of the human genome that pass unshuffled from parent to child. These segments of DNA are only changed by occasional mutations. When these mutations are passed down to succeeding generations, they become markers of descent DNA that doesn't change as much.

A recent example from the National Geographic program The Human Family Tree highlights why the DNA marker is more important than your appearance. One of the shows participants, Dave, considered his heritage to be African-American(because visually this is what he saw) whereas upon testing his marker indicated that his marker came out of C. Asia and eventually Europe, which was the same marker of another participant George who considered his ancestry Greek. Essentially at the genetic level appearance based labels like African American and Greek break down, and for food adaptability ratings I predict they will also lose some of their usefulness(depending on if the adaptation is internal(gut adaptation/organs) or external(skin adaptation for Vitamin D production/absorbtion)).

The genetic/dietary connection can be seen when you compare the map above to the one below of the inability to digest lactose beyond 4 years of age .

In the future I'll post on other areas that may have a genetic connection like wheat and alcohol tolerance.

Next post I'll talk about how I think presumed random sampling leads to underlying bias in nutritional studies and examine how a tweak in experimental design could improve the reliability of research and the replication of results.

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