How People Can Trace Their Heritage Using MtDNA

DNA found in the mitochondria, known as mtDNA has been found to be important for the origin of species. This mtDNA makes it possible to trace people through their mothers as mtDNA only is passed from mother to child and is not passed on from the father.

mtDNA – This refers to mitochondrial DNA, or a DNA that is only found in the mitochondria. This differs from other DNA that is found specifically in the nucleus. mtDNA is specifically based onto the child through the mother and not the father.

Maternal Lineage – base using mtDNA it is possible to trace a family’s history through the maternal line. One mother will give her mtDNA to her children. Then this same mtDNA is passed down to her grand children, and so on. Therefore it is possible to trace a family line back hundreds of years to one single mother.

Mitochondrial Eve – This refers to the matrilineal most recent common ancestor in that all living humans in the world descend from one mother, Eve. This one mother was thought to live 200,000 years ago in East Africa.

Recombination – In genetics this term refers to the mixing of DNA where as DNA chains are broken and then joined to different one. This is how children are different from their parents and the male and female DNA are mixed. However of all the DNA, mtDNA does not go through recombination and is purely inherited from the mother.

Mutations – it is through mutations, or random changes in the DNA sequence, that allow the possibility to trace back to mitochondrial Eve. Mutations in mtDNA occur once in approximately every 3,500 years. These mutations cause branches from the original mtDNA family tree. These branches come to an end when no more daughters are born. Scientists investigate the number of mutations that have occurred in the branches of the family tree and then compare this to the geographical region where Eve supposedly lived.

Mitochondria – This organelle is found inside the cell but outside of the nucleus. It is considered the powerhouse of the cell as this is where ATP is produced; the compound that is the chemical source of energy. Typically within the mitochondria there are between two to ten copies of mtDNA.

Skeletal remains – mtDNA is being used more and more in forensics to help match skeletal remains with missing persons as it provides a lot of information when combined with circumstantial evidence, anthropological evidence and more.

Phylogenic – This refers to evolutionary relationships and mtDNA can asses genetic relationships within species and groups as long as they are not overly distantly related. The mtDNA sequences from several individuals are compared and a network is constructed form the sequences. This then provides a good estimate of the relationships between the groups. In humans this is very easy as the number of sequences of mtDNA are low compared to other species.

Electron Microscopy – This was used to discover mtDNA in the 1960s and refers to the use of a beam of electrons that illuminates and then magnifies an image. This has great resolving power and achieves magnifications of more than 10,000,000x.

Homoplasy – This refers to DNA similarity due to convergent evolution despite the fact that people came from independent origins. Individuals become more alike because of a similar and shared environment and functions, despite the fact that they themselves may have come from widely different areas.

Convergent evolution – It is through this acquisition of similar biological traits despite unrelated lineages that scientists are able to predict future evolutionary changes. Therefore by looking at environments and behavior it is possible to predict which mutations will be successful and which will not. The successful mutations will create new branches in the matrilineal tree while the others will most likely die out.

Anthropology – This is the study of human beings and mtDNA is an important part of this field. In particular mtDNA can show the travel of migration of individuals or not. In many cases when specific mtDNA lines stayed put for thousands of years, specific mutations could accumulate which would be able to separate different cultures, one instance being the separation of the Native Americas from their Chinese ancestors. Anthropologists also showed that the migration of people through North and South America was very fast in comparison as mtDNA is the same in both South and North America.

Recent African Origin of Modern Humans – This is the most widely accepted theory for the origin of modern humans. This theory is linked to mtDNA as it states that humans have a single origin that dates back to Charles Darwin. This theory was completely speculative until mtDNA was able to show evidence of this theory.