Message #68219

[Bianca]

                                       







DNA analysis on Native Americans began in the 1980s, but with rapid technological improvements, research intensified in the early 1990s, Several teams of genetics researchers at prominent American universities have been conducting numerous studies- Although results from early studies showed the expected Siberian-Asia ancestry of the majority of modern Native American tribes, things took an unexpected turn in 1997.

 

At that point it was found that a small percentage of modern Native Americans have an unusual type of DNA then known to exist only in a few locations in Europe and the Middle East. Subsequent research indicated that the European DNA was not the result of genetic mixing after Columbus. In addition, the same DNA was later found in the bone of an ancient American burial confirming that people carrying this unique DNA had entered America in ancient times. However, in July 2001, this unique gene was also found in a small tribe living in the northern Gobi Desert area.

 

The DNA research initially seemed to promise solid proof of not only where the ancient Americans came from, but also when they came. However, as might be expected, ancient DNA research has become a highly contentious issue with several competing sides.


Most of the DNA research on Native American Indians has been done utilizing mitochondria. Every cell In our body contains hundreds to thousands of these tiny, football-shaped organelles. The mitochondria process glucose (sugar) into a usable form of energy for all of our body's functions. The mitochondria are believed to be an evolutional form of bacteria that adapted into a symbiotic relationship with multi-celled life forms. Thus, the mitochondria have their own unique DNA, which is simpler and easier to analyze than the human DNA found in the nucleus.


Mitochondrial DNA (usually abbreviated as mtDNA) is passed to offspring only through the egg. Thus, it is not a combination of male and female genes. It is a haploid gene — meaning that it has only one dose of chromosomes. The haploid mitochondrial DNA shows only the female lineage of a person. Diploid genes are two sets of combined chromosomes, the female set coming from the egg, the male chromosomes from the sperm.


Mitochondrial DNA (mtDNA) is categorized into several types and groups termed haplotypes and haplogroups. That is, there are variations in the genetic code of mitochondria that fit into clusters. These clusters can trace lineage far back into time.