KNOW YOUR HERITAGE: Dr Rick Kittles Breaks Down D N A (617 hits)
DNA is important for tracing ancestry because itís like a record of the history of you as an individual, within your family, community, and within a particular region in the world.
Dr. Rick Kittles, a brilliant, forty five-year old geneticist, who serves as Associate Professor in the Department of Medicine; division of Epidemiology and Biostatistics, at the University of Illinois at Chicago.
Kittles also is the co-founder and Scientific Director of African Ancestry, Inc., a nine year-old, ancestry tracing company with a DNA database comprised of over 25,000 African DNA lineages. EBONY spoke with Dr. Kittles about what DNA is, and how it reveals the hidden past, and complexity of our African-American heritage.
EBONY: Weíve all heard of DNA, but give us a thumbnail sketch of what it actually is.
Rick Kittles: DNA [deoxyribonucleic acid] is the genetic material Ė the chemical thatís in every cell of our body, thatís important for coding different physical features and traits. You receive half of your DNA from your mother, and the other half comes from your father. DNA is very instrumental in terms of coding for things that make us human: skin color, hair texture, eye color, and physical features. But it also [shows] susceptibility to cancer, diabetes, and other diseases. DNA is important for tracing ancestry because itís like a record of the history of you as an individual, within your family, community, and within a particular region in the world. We can use that information to trace where a personís ancestry came from.
We can go all the way back to when humanity started in Africa over 150,000 years ago, or we can look at a more recent window, like for instance, right before the slave trade. Those changes in the DNA are different than the older changes that occurred 150,000 years ago.
EBONY: We know what DNA tells us. What doesnít it tell us?
RK: Itís not going to tell us if a person who just got accepted into Harvard is actually going to be able to graduate [laughs]. It doesnít provide useful information for behavioral or psychological traits. Also, as it relates to overall health, DNA plays some role, but itís not one hundred percent. There are certain changes in the DNA that increase your risk for cancer, but what also plays a very significant role is exercise and lifestyle; what we consider the environment.
EBONY: As far as tracing our ancestry is concerned, are there specific types of DNA that links us back to Africa?
RK: The one thatís really informative for African-Americans is mitochondrial DNA [mtDNA]. Itís passed on through women. Males receive it from their mothers, but they canít pass it on to their kids. It represents the lineage of women in the family. We also look at the Y chromosome DNA, which is a history of the male lineage in the family. There are DNA patterns that are specific to Africans: For instance, thereís what we call a Y chromosome alu polymorphism [YAP] that is found just in West Africa, and is definitive for West African ancestry. But the most interesting thing is, when we look at most African-American men, upwards of thirty five percent of their Y chromosomes donít go back to Africa; but to Europe!
EBONY: Thatís because of slavery; African women mating with European menÖ
RK: Thatís right. Itís really the behavior of slaveholders during slavery and afterwards Ö Itís what we call sex-biased gene flow. Of the genes from Europeans that came into the African-American population, the majority of them came from men.
EBONY: In the series, Professor Gates concluded that virtually all ...