Definition for Mitochondria
Glossary
Mitochondria (relative to Adam and Eve’s creation)
We need to know about mitochondria because it is the key that unlocks our understanding of Adam and Eve’s creation. Does Genesis teach us a symbolic understanding of their creation, or is it a literalistic account? Before defining the word, see how it comes into play in the creation account. How does mitochondria teach us whether Adam and Eve were born, or where they created from the dust of the earth — exactly as Scripture tells us?
In 1987, research undertaken by Rebecca Cann, Mark Stoneking, and Allan Wilson was published in Nature magazine. They concluded that all human beings descended from one female living in Africa approximately 200,000 years ago. They do not suggest that she is the first female human. Rather, travelling backwards through time, it is claimed she was the first female ancestor from whom all subsequent humans share a common set of mitochondrial DNA (mtDNA). It is also believed that Y-chromosome Adam could have existed at a different time-frame than did mtEve. While we will be challenging some of their assumptions, we will not be attempting to determine the validity of the science or the methodology used by the researchers in order to gain the information necessary to reach their conclusions. Some of the conclusions reached by the research authors will, however, be challenged.
Researchers sought to ascertain when and where the woman lived from which all human populations descended (including modern man). To arrive at their conclusions, they used only the mitochondrial DNA from one hundred and forty-seven people from five different geographical regions; specifically, Africa, Asia, Australia, Europe, and aboriginal New Guinea.[1]
I will now link to the three parts of the answer to those questions. Part I answers the question through the Magisterial writings of the Church. Part II answers the question from a scientific standpoint. Part III shows why any discussion starting with the premise that they were born from animal man is theologically problematic — even heretical. So, what is the definition of mitochondria?
What Is Mitochondrial DNA & How Does It Differ from Nuclear DNA?
To begin with, ‘nuclear DNA’ is the DNA that is located in the enclosed nucleus of every cell. Nuclear DNA contains approximately 30,000 genes in every molecule. By comparison, mtDNA contains only thirty-seven genes.[2] Mitochondrial DNA is located outside of the cell nucleus, in the watery part of cell, i.e., the cytoplasm. Mitochondrial DNA is an organelle, which are specialized structures that are dedicated to certain functions. They are usually enclosed within their own lipid membrane (resembling the outermost cell membrane).[3] What is the special process reserved for mtDNA? The mtDNA organelle performs several functions within the cell. Two of which are: 1) converting food into energy which is usable by the cell, and 2) the regulation of cell death (apoptosis).[4]
In human reproduction, the sperm cell of the father and the egg cell of the mother each contain 23 chromosomes which contain a complete set of their nuclear DNA. When the egg becomes fertilized, the two sets of DNA combine through a process aptly called recombination. The result of this recombination is that the zygote cell contains only 23 chromosomes (not the original 46). Both the sperm cell and the egg cell contain mtDNA. However, the resulting offspring (i.e., the fertilized egg), regardless of gender, gets its mtDNA only from the mother.[5] So what happens to the father’s mtDNA? It does not survive the fertilization process. Immediately upon entering the egg, the father’s mtDNA is attacked by enzymes which virtually always kills the mtDNA of the sperm cell. While there are hypotheses regarding the phenomenon, it is still a mystery as to exactly why and how this occurs.[6]
What Is Mitochondrial DNA & How Does It Differ from Nuclear DNA?
Researchers used mtDNA because it does not go through the recombination process which is necessary to combine the two separate sets of chromosomes into one set. Recombination could result in genetic mutations that are not the result of the normal evolutionary processes, thus tainting the ‘molecular clock’ that would be used to estimate mtEve’s placement in historical time. The passing of mtDNA from mother to offspring results in only minor random mutations to mtDNA sequence.[7] Furthermore, there are multiple identical copies of mtDNA in each of the mother’s cells. Researchers believed the lack of recombination would result in a greater sensitivity of mtDNA across generations in small communities that would then expand into large populations.[8] Cann et al, estimated that two to four percent of mtDNA mutates every million years.[9]
In the research conducted by Cann et al, they used two assumptions. First, all mtDNA came from the maternal side of the offspring’s parents. Second, all the mtDNA within each individual was identical. It is the first assumption that are focused on when studying so-called mtEve.
ENDNOTES:
[1] Dorothy R. Haskett, “‘Mitochondrial DNA and Human Evolution’ (1987), by Rebecca Louise Cann, Mark Stoneking, and Allan Charles Wilson,” (The Embryo Project Encyclopedia, Arizona Board of Regents, 2014), https://embryo.asu.edu/pages/mitochondrial-dna-and-human-evolution-1987-rebecca-louise-cann-mark-stoneking-and-allan October 10, 2014.
[2] Ibid.
Cited by Haskett: Pakendorf, Brigitte and Mark Stoneking. "Mitochondrial DNA and Human Evolution" Annual Review Genome Human Genetics 6 (2005): 165–83.
[3] Natalie Andrews, “What is an Organelle in a Cell?,” Sciencing, https://sciencing.com/organelle-cell-8733502.html, April 24, 2017.
[4] National Institutes of Health, “What is Mitochondrial DNA?,” U.S. Department of Health & Human Services, https://ghr.nlm.nih.gov/pri mer/basics/mtdna, January 09, 2018.
[5] Haskett, https://embryo.asu.edu/pages/mitochondrial-dna-and-human-evolution-1987-rebecca-louise-cann-mark-stoneking-and-allan.
[6] Weizmann Institute of Science. "Inheriting Mitochondria: Where does your father's go?." ScienceDaily. www.sciencedaily.com/releases/2014/05/140515095637.htm (accessed January 11, 2018).
Cited by ScienceDaily: Yoav Politi, Liron Gal, Yossi Kalifa, Liat Ravid, Zvulun Elazar, Eli Arama. “Paternal Mitochondrial Destruction after Fertilization Is Mediated by a Common Endocytic and Autophagic Pathway in Drosophila.” Developmental Cell, 2014; 29 (3): 305 DOI: 10.1016/j.devcel.2014.04.005.
[7] Haskett, https://embryo.asu.edu/pages/mitochondrial-dna-and-human-evolution-1987-rebecca-louise-cann-mark-stoneking-and-allan.
Cited by Haskell: Cummins, Jim. "The Role of Maternal Mitochondria during Oogenesis, Fertilization and Embryogenesis." Reproductive BioMedicine Online 4 (2002): 176 – 82. http://download.journals.elsevierhealth.com/pdfs/journals/1472-6483/PIIS1472648310619372.pdf.
[8] Haskett, https://embryo.asu.edu/pages/mitochondrial-dna-and-human-evolution-1987-rebecca-louise-cann-mark-stoneking-and-allan.
[9] Ibid.