College Writing II
25 September 2012
Back to Your Roots
The origin of man has always been a question that the human race has tried to answer, but could never quite pinpoint. Homo Sapiens now know the exact start of man, due to advances in harvesting mitochondrial DNA. “Markers” are used to trace ancestry. These markers are found through DNA Sequencing and SNP testing. The general acceptance is that the human race stemmed from a woman referred to as “Mitochondrial Eve.” It is estimated that she lived 200,00 years ago in Africa (Rice University). Margit M. K. Nass and Sylvan Nass are accredited in discovering Mitochondrial DNA, or mtDNA in 1960 using electron microscopy (Rice University). DNA is found in two places in the cell; it inhabits the nucleus and the mitochondria. Mitochondria are known for their ability to produce Adenosine Triphosphate, or ATP in the cell, but scientists have found their own specific DNA to be helpful in determining lineage.
Within the mitochondria, numerous copies of DNA are found. The mitochondrial DNA is therefore more practical to use than the one copy in the traditional nucleus. The mitochondria itself has it’s own genome and has its own genes. The tiny organelle has a mere 37 genes that mainly remain unchanged (Rice University). According to Genebase, the mtDNA is also much smaller than nucleic DNA. Nucleic DNA ranges from 49,530,000 to 247,200,000 base pairs the mtDNA only ranges from a mere 16,569 to 16,571 base pairs. mtDNA is round; this round shape is also referred to as a plasmid, unlike traditional linear nucleic DNA. The plasmid is divided into four main regions. It contains a D-loop, Transfer RNA, Ribosomal RNA and a region that genes make proteins. The Transfer RNA, Ribosomal RNA and the gene area are referred to as the “coding region.” The D-loop is also known as the hypervariable region. This area is considered to be a non-vital part of the mtDNA. This is because mutations in...