What do we know about mitochondria and why is it a unique organelle of a eukaryotic (nuclear) cell?
The mitochondrion is the only carrier of its own DNA, different from ours. The analogue of mitochondria in a plant cell are plastids. These are organelles covered with two membranes, containing their own ribosomes and their own genetic information. They are an essential part of our body because they produce energy in the cells. In essence, these are energy stations in which something is constantly “burned”, resulting in the formation of energy.
There is a theory that both of these organelles were originally prokaryotic (pre-nuclear) organisms that entered eukaryotic cells and stayed there for millions of years, causing an energy revolution on Earth. This theory is supported by the presence of two membranes (one is its own, and the second is the host membrane) and DNA of the bacterial type. Mitochondrial DNA is not highly conserved and has a high mutation rate, therefore it is a good object for studying the evolutionary relatedness of organisms.
Mitochondrial DNA is even associated with a unique type of heredity – matroclinic (characterized by the predominance of the properties of the maternal organism). Those. This is heredity exclusively through the female line, since the zygote (an egg fertilized by a sperm) receives mitochondria only from the egg, and not from the sperm.
The question arises from the category “What came first: the chicken or the egg?” Who or what started this whole process of mitochondrial DNA transmission? After all, absolutely every person on Earth has it. And it all started with Mitochondrial Eve – the woman from whom all modern humanity inherited that same one. Who was she and where did she live?
Most likely, our heroine lived in Africa 200,000 years ago. This lucky woman became the only one in her generation whose female descendants have survived to this day.
In fact, it is the closest common ancestor of all humanity through the female line. Does Eve have her own biological Adam? Yes, the DNA of the Y chromosome in all men on the planet comes from the “molecular biological Adam”.
It sounds amazing and almost fabulous, but still, biblical Eve and biological Eve are different concepts. It was not a single woman, but a certain homogeneous genetic population that gave it all a start. It is not known exactly what came before this population.
An important event in the world of genetics was Brian Sykes’s book “The Seven Daughters of Eve,” which reveals the theory of human mitochondrial inheritance.
Sykes explains the principles of human evolution, features of mitochondrial and ancient DNA. In the book, Sykes reveals a theory about the classification of all modern Europeans into seven mitochondrial haplogroups. The mitochondrial DNA of representatives of each group has its own specific mutations, which can be traced through the mother’s line all the way back to the very prehistoric woman who gave rise to one of the seven groups. Each “clan mother” has her own name: Ursula, Xenia, Helena, Velda, Tara, Katrine, Jasmine. And haplogroups are named after them (the first letter of the name).
Is there anyway I can find out the name of my “prehistoric mother”? Yes! There are commercial genetic tests that can determine ethnicity based on haplogroup.
Interesting fact: information about the structure of the mitochondrial genome was used by scientists to identify the remains of the Romanov royal family. For identification, the comparative material was data on the study of the genetic material of the late Prince Philip, which were taken directly from the book by Brian Sykes.
Would you like to find out your haplogroup and did you know about the seven daughters of Eve?
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