MtDNA is known to come only from the mother to the offspring with no father’s contribution since their mtDNA is wiped from the children’s cells. The paternal mitochondria are found to have a self-destructive mechanism that is activated at the instance when the sperm meets the ovum. Maternal inheritance is when the mtDNA is transferred from mother to offspring and helps in tracing maternal ancestries. There are findings from the hypothesis developed by Prof Bryan Sykes called The Seven European Daughters of Eve Matriarchal Groups as outlined below.
Sykes examined DNA from fossils and realized that the relationship of individuals is recorded based on their DNA sequence, especially mtDNA. According to Sykes, mtDNA is inherited exclusively from mothers and mutates slowly and steadily (Amorim et al., 2019). From his research, Sykes asserts that scientists can trace one’s genetic makeup to ancient times when particular strands of DNA are identified as passed through the maternal line. He explains DNA as a blueprint of all life, acting as a map to one’s genetic information, and is needed for one’s growth and reproduction. He discusses in his hypothesis how genetic traits are inherited from generation to generation.
According to Sykes, mtDNA is a type of DNA that is only succeeded by the mother, and from the hypothesis, this genetic material enables researchers to formulate matrilineal family trees. MtDNA allows scientists to stretch back to many generations showing the lineage from mother to mother (Amorim et al., 2019). Sykes found out that tracing back ancestral mothers can be done by analyzing infinitesimal variations found in the mtDNA of individuals and can be used in finding others with the same genetic blueprint. Inheriting this genetic material helped Sykes form a basis for creating DNA trees for humans and this enabled him to trace the origin of individuals as he was doing investigations in a mass grave.
From the hypothesis, Sykes denotes that all Europeans can be traced back to one of the female ancestors using mtDNA. Out of the seven, each one of the women has different haplogroups depending on the characteristic mutation, although they share a common ancestor referred to as the Mitochondrial Eve (Jabbar & Al-Rashedi, 2021). This discovery enabled individuals to understand that modern Europeans are likely to be indigenous since he genetically linked them to their prehistoric ancestors and traced back migrations that occurred during early times. Sykes classified modern Europeans into seven groups by tracing their maternal line tied to a specific ancient woman referred to as clan mothers.
The clan of Ursula was considered to be the oldest with direct descendants among the modern Europeans covering about 11% of the current population originating from all parts of Europe. The Xenia clan is the second oldest among the seven with around 7% of Europeans belonging to it today (Oikkonen, 2018). The clan of Helena is the largest and the most successful, containing over 41% of modern Europeans. This clan has several branches and is widespread all over Europe, with a part of it in southern France and Spain. The Velda clan is the smallest, comprising about 4% of indigenous Europeans who live in northern and Europe, Finland, and Norway. The Tara clan has less than 10% of modern Europeans and contains many branches that are widespread in western and southern Europe (Oikkonen, 2018). The clan of Katrine is medium-sized, with its members living in northern and central parts of Europe. Jasmine clan is the second largest among the seven clans, with its origin in Europe. The Ulrike clan is not originally among the seven clans, although it is included among the important clans and is found today in north and eastern Europe.
From the hypothesis developed by Sykes, the genealogy of the seven women was discovered by tracking them back with the aim of reconstructing their mtDNA sequences and then finding ancestral connections among them. Maternal lineage helped find the relationship between clans where Helena and Velda clans were found to be closed, sharing a common ancestor. Similarly, Jasmine and Tara’s clans shared a common ancestor and this was also the case with Katrine and Ursula. It is the development of mtDNA that enabled Sykes to trace and guess about the lives of the clan mothers since through it he was able to assess the genetic makeup of modern Europeans (Baquero-Méndez et al., 2021). As a result, classifying them into seven groups as possible, with each of the groups containing a particular characteristic mutation tied to a specific prehistoric woman.
Mitochondrial DNA can be found in different organisms, including humans, plants, and algae, among others. This is a genetic material that is inherited from mothers, especially when it comes to multicellular organisms. Simple dilution is a mechanism that causes this maternal inheritance since the human sperm has cells that cause degradation after fertilization making it difficult to be inherited. This inheritance helps in tracking down the maternal ancestry of individuals to their ancient mothers. The hypothesis developed by Sykes was based on this concept where he conducted a sequencing that enabled him to determine the maternal lineage of Europe and through it, their origin was discovered. There are instances where male inheritance may occur, although the instances are rare and it occurs in some mammals, mice, and in rock chickens. MtDNA is therefore important in tracing the geographical distribution and investigating expansions and migrations and can be applied in forensic science.
References
Amorim, A., Fernandes, T., & Taveira, N. (2019). Mitochondrial DNA in human identification: A review. PeerJ, 7, e7314.
Baquero-Méndez, V., Rojas-López, K. E., Zurita, J. E., Cobo, M. M., Fernandez-Salvador, C., Ordóñez, M. P., & de Lourdes Torres, M. (2021). Genetic characterization of a collection of Tsantsas from Ecuadorian museums. Forensic Science International, 110879.
Jabbar, S. M., & Al-Rashedi, N. A. (2021). Mitochondrial DNA control region variation in an Iraqi population sample. International Journal of Legal Medicine, 135(2), 421-425.
Oikkonen, V. (Eds.). (2018). Mitochondrial Eve and the affective politics of scientific technologies. In Population Genetics and Belonging (pp. 23-71). Palgrave Macmillan.