In this article, Silvio Mattacchione discusses Mitochondrial DNA and the Significance of the Maternal Line in breeding Racing Pigeons. Below is an excerpt of the article that begins with What Is Mitochondrial DNA?
Rather than me reinventing the wheel I am going to quote from dnaheritage.com as they have defined Mitochondrial DNA As:
There are two kinds of DNA that are found in a cell: nuclear and mitochondrial. Nuclear DNA is found within the nucleus of the cell and is composed of two sources of DNA. One source is the egg (from the mother) and the other is the sperm (from the father). This is the type of DNA that defines us as individuals and is most often used in forensic or paternity cases. In terms of forensic cases, the nuclear DNA of a specimen from a crime scene is compared to a specimen from a suspect to see how similar they are; in terms of a paternity suit, the nuclear DNA of the child is compared to the nuclear DNA from the father to see if the father contributed to the child’s DNA.
Mitochondrial DNA (mtDNA) is contained in the mitochondria of the cell. The mitochondria are organelles located outside the nucleus in the cytoplasm of the cell. These organelles are responsible for energy transfer and are basically the “powerhouses” of the cells… This form of DNA is in short strands and therefore does not mutate or change form very quickly – it is relatively stable and can be compared across several generations. Mitochondrial DNA is only passed along the maternal line – so if we want to compare a sample … we have to obtain a blood sample from the mother or any of the siblings (who would share the same sequence of mtDNA as the mother), but in terms of nieces or nephews, we could only obtain it from a sister’s children (a brother’s child would obtain his or her mtDNA from the mother who would not be related).
Your maternal ancestry can be followed back using a special type of DNA called mitochondrial DNA. We call it mtDNA for short.
Mitochondria are found within each of our cells. Their main job is to produce energy so that when we run up a flight of stairs, just enough energy is produced for our cells.
However, it’s the way that the mitochondria and, more importantly, the mtDNA inside is passed on to the next generation that is of most interest to genealogists and people looking into their past.
In one quick sentence, females pass mtDNA onto their offspring.
Therefore, everyone will have received mtDNA from their mother and in turn, those mothers received their mtDNA copies from their mothers too. In this way, the path of the mtDNA has travelled down the generations through the direct maternal line. Reference: dnaheritage.com