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7.3: Anthropological Genetics

  • Page ID
    133349
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    Learning Objectives
    • Define Anthropology and explain how anthropology and genetics are connected.

    • Identify breakthroughs in genetics that contributed to anthropology. 

    • Apply anthropological knowledge and genetic techniques in real world situations.

    • Determine when scientific work is or is not appropriate using anthropological ethics.

    Section 1: What is Anthropology?

    Anthropology (Anthropo means human) is the scientific study of all human species (including extinct ones) and nonhuman primates, and includes the impact of humans on the world throughout all time. This includes humans’ impact on the environment, other living organisms, and other human populations. Anthropology often examines cultures and how they develop, how languages develop and evolve over time, how humans have impacted animals and the environment, how humans interact with one another, belief systems like religion and mythology, and more. Anthropology is inherently interdisciplinary since humans have interacted with and impacted most fields of science. Anything humans are involved in is anthropological in nature. That said, anthropologists often specialize in four categories: Biological Anthropology, Archaeology, Cultural Anthropology, or Linguistic Anthropology. Biological Anthropology is what will be the focus of this section.

     

    • Biological Anthropology- the study of human (and non-human primate) evolution and adaptation. This field includes such specialties as forensic anthropology, primatology, and human osteology, among many others. 

     

    Video \(\PageIndex{1}\): Biological anthropology is all about studying human biology in an evolutionary framework. How did Homo sapiens come to be? Perhaps more importantly, how did this field come to be, and how has it developed over time? Let's take a look at the history of this field now!. (Professor Dave Explains via History of Biological Anthropology (Up to Genetics) - YouTube)

     

    Every pre-health major who intends to work with humans will be conducting anthropological work, even if it is never called that. Every teacher sharing knowledge is contributing to anthropology, and every lesson learned came from anthropological work and is inherently anthropological in nature.

     

    Video \(\PageIndex{2}\): Once the field of genetics was developed, our understanding of biology was completely transformed. How did this specifically impact the field of anthropology? From Mendel's laws to the Human Genome Project, let's learn about how our ever-expanding understanding of DNA elucidated the history of Homo sapiens and other hominid species. . (Copyright Professor Dave Explains via https://www.youtube.com/watch?v=RpUv3GeyMoo)

     

    Section 2: Humans, and How Genetics Contributed to Anthropological Understanding

     

    Anthropological techniques enabled science to begin reconstructing the evolution of hominid species. Hominids diverged from other primates millions of years ago and the groups began evolving independently of one another. Before we could sequence genes, these techniques were used to seriate these hominins. To do this, anthropologists look at data regarding the body in order to determine certain characteristics. 

     

    clipboard_e51d22b257436a7f846a499011038de07.png
    Figure \(\PageIndex{1}\): The position of the foramen magnum differs between quadrupeds (example dog skull shown) and bipeds (modern human skull shown). The gorilla is an intermediate with an intermediate position. (Copyright; Tosha Aleck, UALR Department of Anthropology.)

     

    For example, we know that bipedal hominids evolved when they did based on the fossil record. Creatures that walk on four legs have a foramen magnum, the opening through which the spinal cord passes, that is situated toward the back of the skull. In contrast, bipedal hominids have a foramen magnum that is situated at the base of the skull. Further features are factored in, such as the size of the brain case, dentition, orientation of certain joints, and body size, among others. Certain features of the body, such as whether or not the epiphyseal plates are fused and the size of the pelvis if it belongs to an adult skeleton, can help us further identify remains. These techniques are also minimally invasive and do not result in destruction of any part of the remains, while genetic techniques require a sample. 

     

    For some of these ancient species, very little remains still exist and are known to us, so genetic techniques are used sparingly. Whenever possible, dating techniques are used on suitable materials found in situ with these remains to determine its age range. However, DNA sequencing has been used to do such archaeological work as reconstructing the influx of humans into North America. As technology continues to advance, it has become feasible for scientists to sequence genetic material that is both very old and from a very small sample. We just have to find viable DNA to sequence, and in some of these ancient ancestors there is not a lot of DNA left to recover.

     

    File:Capacidade craniana dos hominínios.jpg

    Figure \(\PageIndex{2}\): Timeline of hominid evolution showing change skull morphology with brain capacity over 4 million years. (Photo copyright  Creative Commons Attribution-Share Alike 4.0 International via Wikimedia Commons)

     

    The only currently extant species of hominids is Homo sapiens. However, proof of the overlap of certain species can be found in the DNA of some people. Neanderthal DNA is found in approximately 1-4% of living humans and Denisovan DNA (not represented in the figure) is found in 4-6% of living human populations. Modern humans, Homo sapiens, have existed for approximately 300,000 years. The first modern humans emerged in Africa and spread out over time from there. 

     

    As these populations got further from the equator, the UV levels dropped, allowing offspring with lighter skin tones to live to adulthood and reproduce. Certain human populations experienced periods of isolation from outside gene flow. When these periods are extended over many generations, this can eventually produce phenotypic variations between the isolated population and other populations. This accounts for the differences in ethnicity seen in different regions of the globe.

     

    Video \(\PageIndex{3}\): What’s a human? And how did we become humans, anyway? In this episode of Crash Course Biology, we’ll meet some of our closest relatives and trace how we evolved into the brainy, inventive, complex species we are today.  (Copyright; Crash Course via How Did Humans Evolve? Crash Course Biology #19 - YouTube)

     

    Before modern dating techniques were discovered, human evolution was determined using seriation techniques to provide order to morphological and evolutionary changes seen in the fossil record for hominids. This was followed by the advent of various absolute dating techniques, which allowed science to determine where fossils fall within the true timeline. Now, genetic analysis has allowed us to create an even more accurate reconstruction of how modern humans evolved.

     

    The Human Genome Project

    One of the most well known, if not the best known, works regarding human genetic analysis is the Human Genome Project, or HGP. The HGP was a multibillion dollar project featuring international collaboration to sequence the entirety of the human genome. The project was launched in 1990 and completed in 2003. This international collaboration also saw legislators get involved in order to ensure the knowledge could not be patented and had to be shared freely with everyone. These legislators  included the U.S. President Bill Clinton and then Prime Minister Tony Blair. Further legislation was introduced in the wake of the HGP to protect people from being discriminated against based on their genetic information, including the Health Insurance Portability and Accountability Act (HIPAA) in 1996 and the Genetic Information Nondiscrimination Act (GINA) in 2008.

     

    This project helped science determine that all currently living humans share 99.9% the same DNA no matter their phenotypic differences. This work proved that humans are definitively a single species and race. Most of the variations between humans are SNPs. There is still much more to learn about the human genome, despite knowing its sequence. As with many scientific breakthroughs, answering one question (sequencing the human genome) created many more unanswered questions. 

     

    Figure \(\PageIndex{3}\): The Human Genome Project (HGP) Timeline contains major milestones in genomics from 1865 to 2003. (Credit: Darryl Leja, NHGRI via genome.gov)

     

    Section 3: The Ethics of Working with Humans

     

    Anthropologists are passionate about humans. Otherwise, you would have chosen to work with another species! Humans are complicated subjects when compared to other living organisms. Humans have independent thought, their own feelings and drives, and a variety of beliefs that can impact how people view the world. In order to conduct science pertaining to humans, a different set of ethics comes into play versus when we work with animals.

     

    What should I do if I want to work with humans or human remains?

    Professional societies are a source of information regarding standards and ethics in their fields. 

     

    The American Anthropological Association provides guidance on ethics when working with humans or humans remains.  

    1. Do no harm.

    2. Be open and honest regarding your work. This also means you should publish your findings regardless of outcome and as quickly as possible.

    3. Obtain informed consent and necessary permissions.

    4. Weigh competing ethical obligations due collaborators and affected parties.

    5. Make your results accessible.

    6. Protect and preserve your records.

    7. Maintain respectful and ethical professional relationships.

    This link AAA Statement on Ethics - The American Anthropological Association includes further explanations of these guidelines.  

     

    The Society for American Archaeology provides additional guidance to consider when dealing with human remains:

    1. Stewardship- You are managing these remains for all parties. Take responsible care of this person, including being respectful of that person’s beliefs and the beliefs of their descendants.

    2. Commercialization- Never use human remains for profit. Never sell any goods belonging to the deceased, including data about them.

    3. Ensure Safe Educational and Workplace Environments- Always be mindful of respecting others, including the deceased. Be respectful of others working around you as well. Treat everyone equally. Free speech and respectful open debate are encouraged when interpreting the data. Differing perspectives are welcome!

    Ethics in Archaeology (saa.org)

     

     

    Working with humans requires a lot of respect and empathy, and this extends to being considerate of the deceased. A person’s rights and autonomy do not end at their death, so we must respect their wishes for how to treat their remains. Even when we are granted permission to use a person’s remains for scientific research, we must aim to conduct this work with respect to the deceased and their descendants. 

     

    When working with remains, handle them with care. Bones should be handled over a cushioned surface. The skull should always be picked up with care. Do not use the eye orbits, foramen magnum, or zygomatic arches to pick up a skull. Carry it with both hands. Remember that even a human skeleton was once a person. Certain groups of people have specific regulations for handling remains belonging to their populations. In the United States, this often relates to the handling of Native American remains and funerary objects. The Native American Grave Protection and Repatriation Act, or NAGPRA, was enacted in 1990 and provides protections to these groups. Prior to this legislation, Native American remains were often excavated without regard for the remains or the descendant communities, who often have strong ties to their ancestors. 

     

    Science has a long and questionable history with misusing subjects in experiments. Examples include the history of animal treatment, human rights violations such as the Tuskegee experiment, and even the history behind HeLa cells (referenced in 1.3.1). Throughout history, certain groups have faced challenges receiving adequate medical care. Henrietta Lacks was an African-American woman who was diagnosed with cervical cancer in 1951. She received treatment for her cancer at Johns Hopkins Hospital in Baltimore, MD, one of the few hospitals at the time who treated African-American patients for cancer. While undergoing treatment, a sample was taken from Mrs. Lacks’ tumor. Dr. George Gey, a physician employed at Johns Hopkins, was looking for “immortal” cells that could be used in cancer research. The cells within this sample fit the bill. The cells survived and multiplied at high rates; they are still used today. Mrs. Lacks passed away in late 1951. While the cells got their name from Henrietta Lacks, HeLa cells, Mrs. Lacks was never told this sample was taken or used. Informed consent was never obtained, and Mrs. Lacks and her family were not credited in any way until decades afterward. Her cells have contributed to cancer research and the development of pharmaceuticals for polio, Parkinsons, and leukemia. Her cells have saved countless lives. Some of the scientists who used the cells went on to win the Nobel Prize. Mrs. Lacks played a pivotal role in all of these breakthroughs, and continues to contribute to scientific understanding. In order for science and medicine to heal the misgivings people can have about participating in things like clinical studies, we must ensure we are always honest, objective, and obtain informed consent.

    Figure \(\PageIndex{4}\): Henrietta Lacks. (Photo source: NIH)

     

    Video \(\PageIndex{4}\): In 1951, Henrietta Lacks, a black woman from Baltimore, USA, died of cancer. However, cells taken from her body without her knowledge continued to grow and multiply even after her death. They became the first 'immortalised human cell line' and changed medical science forever. HeLa cells have helped to create cancer treatments, vaccines and have even furthered our understanding of space travel. Now, 100 years on from Henrietta's birth, her immortal cells are helping researchers develop a Covid-19 vaccine. (Video by Daniel John Animations by Lily Baker. BBC Global via YouTube.)

     

     

    References and Resources: 

    AAA Statement on Ethics. 15 March 2024. <https://americananthro.org/about/pol...ent-on-ethics/>.

    Animal Welfare Act Timeline. 15 March 2024. <https://www.nal.usda.gov/collections...re-prohibition>.

    BBC Global. Henrietta Lacks: The 'immortal' cells that changed the world. 30 October 2020. <https://www.youtube.com/watch?v=pgB1IqGp8BE>.

    Dehay, Colette and Henry Kennedy. Evolution of the Human Brain. 31 July 2020. <https://www.science.org/doi/full/10....cience.abd1840>.

    Etheredge, Laura. Henrietta Lacks. 7 March 2024. <https://www.britannica.com/biography/Henrietta-Lacks>.

    Ethics in Archaeology. 7 March 2024. <https://www.saa.org/career-practice/...in-archaeology>.

    Genetic Information. 16 June 2017. <https://www.hhs.gov/hipaa/for-profes...%20or%20Titles>.

    Genetics vs. Genomics Fact Sheet. 7 September 2018. <https://www.genome.gov/about-genomic...netic%20makeup>.

    Gibbons, Ann. Ancient Skulls May Belong to Elusive Humans Called Denisovans. 2 March 2017. <https://www.science.org/content/arti...led-denisovans>.

    Health Insurance Portability and Accountability Act of 1996 (HIPAA). 27 June 2022. <https://www.cdc.gov/phlp/publication...pic/hipaa.html>.

    Hernandez, Joe. Henrietta Lacks' descendants reach a settlement over the use of her 'stolen' cells. 1 August 2023. <https://www.npr.org/2023/08/01/11912...t-stolen-cells>.

    How Genetics Interacts with Biological Anthropology. 29 January 2024. <https://www.youtube.com/watch?v=RpUv...Uwimvg&index=3>.

    Human Genome Project. 24 August 2022. <https://www.genome.gov/about-genomic...genome-project>.

    Introduction to Anthropology. 2 January 2024. https://www.youtube.com/watch?v=LYUz...SXp8vqxAUwimvg.

    Leen, Sarah. Human Skin Color Variation. 3 January 2024. <https://humanorigins.si.edu/evidence...olor-variation>.

    Professor Dave Explains. History of Biological Anthropology (Up to Genetics). 15 January 2024. <https://www.youtube.com/watch?v=FZUY...Uwimvg&index=3>.

    The U.S. Public Health Service Untreated Syphilis Study at Tuskegee. 5 December 2022. <https://www.cdc.gov/tuskegee/timeline.htm>.

    Waters, Michael R. Late Pleistocene Exploration and Settlement of the Americas by Modern Humans. 12 July 2019. <https://www.science.org/doi/full/10....cience.aat5447>.

     

    Author

    This page was written and curated by Tosha Aleck at the University of Arkansas - Little Rock.


    This page titled 7.3: Anthropological Genetics is shared under a CC BY license and was authored, remixed, and/or curated by Stefanie West Leacock.

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