DNA role in tracing ancestry, behavior and personal identity

Published on December 1, 2007

By Chong Singsit

 

December 1, 2007

 

Genetics and the Kuki society

 

Introduction: In a changing world, the laws of hereditary discovered by Augustinian monk George Gregory Mendel has stood the test of time, unchallenged, and is still the basis by which relationships among living organisms is explained. There is no denying that genetic science has impacted our society, the government, science and technology, and the moral code of conduct.

 


Today courts decide the fate of accused criminals based on DNA testing, the eating of genetically modified food, and the practice of gene therapy; all of which will one day be routine rather than the exception. The landmark sequencing of the human genome unlocked the genetic mystery of the human physiological functions and promised superior individual healthcare, including designer drugs. While the technology is astonishing, it also interferes with personal privacy and exposes individuals vulnerable to insurance company’s decisions about personal healthcare.

 

This article is an excerpt of a seminar given on Thanksgiving Day November 22, 2007 at a gathering of the Kuki-Chin community at Tulsa, Oklahoma, USA to celebrate Chavang Kut (Harvest Festival). The primary objective of this article, however, is the role of genetics in tracing human origin, ancestry, and personal behavior. People have wondered for ages how traits are inherited from one generation to the next, and why children often look more like one parent than the other, though most offspring possess blended characteristics of both parents.

 

DNA testing is the only empirical evidence that genetic imprinting on the chromosomes have taken place, establishing the laws of hereditary. While the role of DNA in ancestry study is more discreet, the influence of genes on human behavior is harder to establish. Certain individuals may be born with genetic conditions that are likely to exhibit aggressive behaviors. The role of DNA in tracing individual identity may be harder to establish because of the environmental components that influence gene expression. What can our genes tell us about who we are? Do our genes affect behavior, personality, and self? Is there a connection between genetic structures and specific behaviors?

 

How should we respond to the concept of freedom and responsibility? Every genetic trait must be tempered with personal responsibility. If our genes direct us to behave in a certain way, can we evade the consequences of that action? Our founding fathers were wise to acknowledge God by inserting a statement in the constitution “all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are life, liberty and the pursuit of happiness.”  It is true that certain behaviors may have genetic components while others are acquired; nevertheless, there is no excuse for irresponsible behavior for normal human beings carrying 23 chromosome pairs.

 

DNA is the abbreviation for deoxyribonucleic acid, which is the genetic material present in the cells of all living organisms. DNA is the fundamental building block for an individual’s entire genetic makeup. A person’s DNA is the same in every cell (with a nucleus). The DNA in a person’s blood is the same as the DNA in their skin cells, semen, and saliva. Genetics is the study of genes and hereditary. Since the discovery of DNA “the molecule of life” by James Watson and Francis Crick, at the University of Cambridge in 1953, molecular biologists have made many advances in the understanding of DNA and other nucleic acids. 

 

DNA is a language whose alphabet has 4 letters, adenine (A), cytosine (C), guanine (G), and thymine (T). Cells read the letters and make a copy (transcription) into a slightly different language called messenger RNA (mRNA), which then translates into a totally different language called proteins.  Those sentences are called genes. DNA is self replicating and self perpetuating and translates its message into protein.

 

Tracing ancestry based on DNA is not just an academic exercise, but also has other practical applications. A geneticist at Howard University offered commercial genetic ancestry tracing to African-Americans who wanted to trace their genetic lineage back to the areas of Africa from which their ancestors were captured and brought to America as slaves (Elliott and Brodwin 2002). The emergence of several commercial genetic testing ventures offering fee-for-service paternity testing, tests for evidence of Jewish ancestry and Native American ancestry.

 

Owing to the practice of close marriages, social structure and culture within these two societies (Jewish and Native American), the genetic traits is easily traceable within these communities. Well before the advent of molecular genetics, the tracing of ancestry played an important and controversial part in political identity. While genetic ancestry tracing is becoming increasingly popular, its limitations make the information it reveals subject to misinterpretation. In light of this, it is worth noting genetic ancestry has the potential to disrupt identity claims as well as to corroborate them.

 

Benefits of DNA technology

 

Before we go further, let us consider some of the direct benefits of modern day DNA technology. Growth in DNA technology research has exploded the last two decades – moving from classical genetics to nanotechnology (the engineering of functional systems at the molecular scale). The production of human vaccines and the application of gene therapy will soon be routine rather than the exception in medical science. The identity of an individual can be established by matching his DNA and the DNA collected from a crime scene. A signature, in the form of DNA, left at a crime scene, is an irrefutable perfect example of forensic science at work.

 

The genetic engineering of crops for higher yield and other quality traits, and the production and sale of genetically modified organism (GMO) makes agricultural science on the fore front of biotechnology. Genetic testing provides both preventive (for example breast cancer screening) and preferential screening for the determination of the sex of a child. The present generation, with emphasis on freedom of choice, cast additional burdens on marriages resulting in over 50% of marriages ending in divorce with increasing parental disputes and child custody cases. DNA based genetic testing is one avenue to resolve disputes arising from child custody battles.

 

DNA: origin, design and purpose

 

In order to understand the subject, I would like to touch on some basic information about DNA and genetics. It has been said that God gave humanity two books: the Bible and the genetic codes of DNA. The Bible provides the blue print for the spiritual man; the genetic codes provide the blue print for the physical man. There are 60 trillion cells in the human body with each cell carrying 23 pairs of chromosomes containing genetic information from both parents. Each cell is serviced by blood vessels extending 65,000 miles long. Just to understand the complexity of the DNA molecule, let’s compare bacteria vs. human beings.

 

There are about 200 genes and 100,000 DNA units that govern a bacterial structure and function. On the opposite spectrum, there are about 40,000 genes (still in dispute) and 3 billion DNA units in human beings. During the process of human development, these genes are turned on and off at various stages of development. A process that is this precise and tightly regulated must be error free or spontaneous abortion occurs. Oversimplifying the issue has led to the contention that life is just the product of DNA, but as a creationist, I reject this concept and support the idea that God created organisms fully formed as recorded in Genesis chapter 1.

 

Human ancestry, behavior, and origin

 

The human population shares 99.9% of DNA. However, mutations found in the 0.1% that differs can be used to trace ancient genetic ancestry. Since DNA is passed from parents to offspring, accumulated mutations create a genetic family tree that encodes a wealth of information. Scientists have correlated many of these mutations, DNA markers, in the form of a single nucleotide difference and have reconstructed human migration maps dating back many generations. The two main techniques currently used are 1) mapping by diverse DNA sequences (polymorphism) on the Y chromosome to trace paternal ancestry, and 2) mitochondrial DNA to trace maternal lines.

 

Both techniques take advantage of the fact that some genetic material is passed down unchanged from parent to child in the case of the Y chromosome, from father to son; and in the case of mitochondrial DNA, from mother to child (both male and female). There are some limitations: for example,   Y chromosome tracing will connect a man to his father but not to his mother, and it will connect him to only one of his four grandparents: his paternal grandfather. Likewise, mitochondrial DNA traces the maternal line with limits only to maternal contributions. Whenever an egg cell is fertilized, nuclear chromosomes from a sperm cell enter the egg and combine with the egg’s nuclear DNA, producing a mixture of both parents’ genetic code.

 

The mtDNA from the sperm cell, however, is left behind, outside of the egg cell. The fertilized egg contains a mixture of the father and mother’s nuclear DNA and an exact copy of the mother’s mtDNA, but none of the father’s mtDNA. The result is that mtDNA is passed on only along the maternal line. This means that all of the mtDNA in the cells of a person’s body are copies of his or her mother’s mtDNA, and all of the mother’s mtDNA is a copy of her mother’s, and so on. No matter how far back you go, mtDNA is always inherited only from the mother. If you went back six generations in your own family tree, you’d see that your nuclear DNA is inherited from 32 men and 32 women. Your mtDNA, on the other hand, would have come from only one of those 32 women.

 

In 1987 Rebecca Cann et al., examined the mtDNA of 147 people representing all continents around the world. Later, with the help of a computer program, they put together a family tree, grouping those with the most similar DNA together, then grouping the groups, and then grouping the groups of groups. The tree they ended up with showed that one of the two primary branches consisted only of African mtDNA and that the other branch consisted of mtDNA from all over the world, including Africa. Based on this, the most recent common mtDNA ancestor was an African woman.

 

Behavior and personal identity

 

Researchers are finding more and more connections between genetic structures and specific human behaviors, including aspects once considered part of the very core of human personality. In 1993, researchers (Brunner et al.) linked the production of monoamine oxidase, an enzyme that metabolizes several key neurotransmitters to genetic anomaly resulting in lower intelligence, impulsive, aggressive, and criminal behaviors. A single base mutation was located on the X-chromosome and traits were exhibited by the male members of the family while none of the women exhibited these traits.

 

The lack of pairing in XY chromosomes in male permits the expression of a single base mutation in the X chromosome whereas, the expression of a single base mutation is masked in female XX chromosome pair combination. Moreover, the male Y chromosome has no known genes of significant importance.

 

Gender identity may be hard-wired into the brain. Eric Vilain at UCLA compared the activity levels of genes in male and female brains in 10-day-old embryonic mice—days before they developed sex organs.  He found 18 genes that were more strongly active in male embryonic brains, and 36 that were revved up in female brains. The finding suggests that genes play an important role in the early development of sexual identity and perhaps shaping gender.

 

Racial and ethnic groups can exhibit degrees of tolerance to disease incidence, disease severity, disease progression, and response to treatment. In the United States, African Americans have higher rates of mortality than any other racial or ethnic group for eight of the top ten causes of death. U.S. Latinos have higher rates of death from diabetes, liver disease, and infectious diseases than do non-Latinos. Native Americans suffer from higher rates of diabetes, tuberculosis, pneumonia, influenza, and alcoholism than the rest of the U.S. population. European Americans die more often from heart disease and cancer than do Native Americans, Asian Americans, or Hispanics (Berg et al 2005).

 

Based on their findings there are real genetic differences exist among the ethnic and racial divide. The members of these groups can have wide economic, social, and psychological experiences and can be exposed to very different environments as a consequence of their membership in a particular group. These differential experiences and environmental exposures may be used to investigate the biological mechanisms that contribute to health disparities among groups (Berg et al. 2005). In addition, self-identified race, ethnicity, or ancestry can provide measures of population substructure that help avoid false-positive results in association studies.

 

The Kukis society and genetic consequences

 

The Thadou-Kuki society is made primarily of small villages scattered throughout the northeast regions of India, northwest Burma, and sections of Bangladesh. The village chief is the CEO, administrator, and chief law enforcer presiding over village judgeship; in short he is all in all. The population of the village tends to be homogenous because of the strong tendency of clansmen to stick together for trust and security reasons. For example, if the village chief is a Haokip, the majority of the population will be Haokips. The Thadou-Kuki villages are characterized by smaller population units and uniformity of the clans inhabiting them.

 

Both characteristics are precursors to genetic uniformity. From a biological viewpoint, human reproduction plays a role in shaping future genetic structure. It is common to have both the village chief and the majority of the village bear the same surname. From a genetics study stand point, such villages will promote a narrow genetic base and increased genetic risks. Since a typical village is small, this tends to encourage close marriages. (One personal observation: the Kukis love to compete for numbers, such as who has the biggest clan? It is important to be the biggest clan, but this is not desirable in a village setting, criteria for uniformity.  However, number matters at the ballot box.)

 

Marriage among Kukis is unique in that it is customary to marry cousins, one’s maternal uncle’s daughter.  Such practice is normal (called pute chanu kichenpi) but its long term impact on the population will be genetic uniformity. Some of the implications of genetic uniformity by marrying cousins are: 1) less genetic diversity within the village population; 2) less selective advantage; 3) harmful genes will be exposed; 4) smaller circle of courtship; 5) inbreeding depression; 6) reduction in vigor; and 7) less resistance to diseases.  There are some vivid examples of a society experiencing some of the above listed outcome such as the Brahmins and Parsees of India. In light of these observations, it will be highly desirable to not support the marrying of cousins. The ill effects of close marriages eventually show up in the population.

 

The naming of children among the Thadou-Kuki society is unique in that the last syllable of the grand parent becomes the first syllable of the grand child. A physical relationship between the grand parent and the grand child is established and there is continuity of grandparent names.  This way of naming provides additional information that will be useful in the construction of a family tree.  The use of surname is common among Kukis, particularly when conversation occurs across tribal groups. The DNA data can readily be supported by a historical evidence of surname commonly used among Kukis. Calling out a person by his surname may sound funny, yet this is one way DNA data can be supported with historical evidence. 

 

No evidence that Kuki-Chin tribes are part of the Lost Tribe

 

During a question and answer time after a seminar presentation on DNA and ancestry, the topic of the lost tribe of Israel and the Kukis came up. Here is my response based on well known Israeli author and journalist Hillel Halkin. Under Israel’s repatriation program, many Jews from different parts of the world were brought back to Israel since 1948, the year the Jewish state was born in the Middle East.

 

Since becoming a sovereign nation, Israel faced many obstacles and challenges, repatriation was one of them. The Amishav was the main organization in Israel to sponsor the Kuki-Chin-Mizo people who claimed to be of the Lost Tribe of Manasseh, even calling themselves B”nei Menashe (Sons of Manasseh). This claim was never substantiated—to the point that the Israel Ministry of the Interior, in charge of issuing visas and registering new citizens, did not recognize B”nei Menashe as members of the lost tribe.

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A DNA based study was undertaken by Professor Karl Skorecki in collaboration with Professor Laldena, History Department of Manipur University, to establish a physical relationship and to corroborate their claim as B”nei Menashe. Accordingly, about 300 DNA samples were collected to demonstrate if there was any link between the Kuki-Chin-Mizo and typical eastern Mediterranean and the Middle East. The laboratory analysis has shown that, with one or two possible exceptions, they fail to demonstrate any link between Kuki-Chin-Mizo DNA profiles, and the profiles typical of the Mediterranean and the Middle East. It must be pointed out that the two possible exceptions do not prove significant with a lack of positive proof, the fact remains that DNA testing shows no special relationship.

 

Many B”nei Menashe have rejected the idea of genetic testing. They are opposed to genetic testing because of the fear of negative results to undermine their belief in a “lost tribe” origin and call their link to Israel into question. A solid proof and empirical evidence linking DNA profile of Kuki-Chin-Mizo with Jews of the Middle East is what will convince me and others, and will be vital to the continuity of the program. They need not fear the outcome of DNA testing, as it reveals truth, and isn’t truth what we are after? God knows who and where the true lost tribe is, and it is best to have a clear conscience without a cloud of doubt hanging over your head.

 

In closing, it is so vital to understand the role DNA plays in our society, touching lives, delivering hope, creating controversies. It is one of the two books of God’s blue print for life. Take time to read and be aware of some of the new findings and men’s intent to use them independent of God. Let us be those who harness nature for the good of humanity within the confines of God’s principles.

 

Reference:

 

Elliott C., and Brodwin P. 2002. BMJ 300:1459-1471.

Brunner, H. G. et al. 1993. Science 263: 578-580.

Berg Kate et al. 2005. Am. J. Hum. Genet. 77:519-522.

Vilain Eric 2006. Psychology Today Online Publication

Hillel Halkin by Linda Chhakchhuak 2007.05.31

Cann Rebecca 1987.