Category: Genetics

Each cell of the human body contains organelles called mitochondria. Mitochondria were probably originally parasitic bacteria. Through evolution they became symbiotic with human cells, and finally an integral part of the cell. They help cells use oxygen. The DNA in mitochondria is separate from the DNA in the nucleus of the cell. The DNA in the…

Modern humans as well as extinct Neanderthals share a common ancestor who lived about 500 thousand years ago (~25 thousand generations). Mitochondrial Eve All humans living today descend in the female line from a woman nicknamed “Mitochondrial Eve.” This unknown woman probably lived in Africa, perhaps in Kenya, Tanzania or Ethiopia, probably about 150 thousand…

Each of us has inherited mitochondrial DNA (mtDNA), along with the mutations that have accumulated in our individual family lines. Geneticists can test for these accumulated mutations. Individual test results are called a haplotype or mitotype. People with the same cluster of mutations belong to the same haplogroup, and are descended from the same female…

Mitochondrial DNA is long, circular strand of DNA. (Bacterial DNA is also circular.) It is composed of 16,569 smaller units, called base pairs. Each base pair is composed of two nucleotides. There are only four possible nucleotides — adenine (A), thymine (T), cytosine (C) and guanine (G). Each nucleotide has a complementary nucleotide. So, along…