Despite being covered by a massive, permanent ice sheet, Greenland has been continuously inhabited by humans for over a thousand years. Most modern Greenlanders are Inuit whose ancestors migrated eastward from Canada around 1000 AD, bringing technology like kayaks and dogsleds. They eventually settled on the coasts of the world’s largest island, hunting whales and seals. As well as their cultural and historical contributions, the people of Greenland carry important information in their genes. A study by Pedersen and colleagues published in the February issue of GENETICS examines variation in whole exome sequences of 18 Greenlandic Inuit individuals, showing the power this unique population could have for identifying rare genetic variants linked to diseases.
The patterns of genetic variation in any group of organisms, including humans, are closely tied to its size and history. The larger a population, the more genetically diverse it should be, and a migrant population will be less diverse than its source since its genetic diversity is a subset of the larger source population. Human populations from Africa are the most genetically diverse of all because their ancestors were the source for all other groups that migrated out of Africa to populate the rest of the world.
The ancestors of the Greenlandic Inuit journeyed most of the way around the world to get from equatorial Africa to the fringes of the Arctic Circle in Greenland: through Asia and across the Bering Strait to North America, and then across vast northern Canada to Greenland. This epic migration and settlement history is reflected in their genomes. Pedersen and colleagues show that the Greenlandic Inuit population has recently undergone a prolonged bottleneck of around 20,000 years, making it one of the historically smallest and most isolated human populations. When compared to much larger populations, the patterns of variation differ in specific ways.
The study found that Greenlandic Inuit have fewer genetic variants overall than other human populations tested so far, but the variants they do carry occur at higher frequencies. This might reflect the prediction that very small populations see increases in deleterious variation since natural selection is less effective in small groups. To explore this idea, the authors estimated how much of the genetic variation in the Greenlandic population is likely to alter protein function, including potential loss-of-function alleles and variants that alter the amino acid sequence of a protein. However, the evidence was conflicting, and the results depended strongly on the type of model used.
Nevertheless, the increased frequency of certain rare variants compared to other groups could prove a boon for disease association mapping by increasing the statistical power to detect links between gene variants and human diseases. One example is a single nucleotide change in the gene TBC1D4, which has been previously linked to type 2 diabetes. This particular allele is found at a much higher frequency in the Greenlandic Inuit population than other surveyed populations, even though type 2 diabetes is not reported to be more common in Greenland. The authors speculate this difference may be due to compensatory variation elsewhere in the genome since type 2 diabetes is a multigenic trait with many underlying contributing factors. In contrast, sucrase-isomaltase deficiency, a metabolic disease that prevents infants from digesting a certain sugar, is very rare in most populations but affects about 5–10% of people in Greenland. The exome data suggests this is due to the relatively high frequency of a particular frameshift mutation in the SI gene.
By any measure, Greenland is an isolated place. The people who first settled there used their creativity and ingenuity to flourish in a difficult environment, the same way humans have all over the Earth. Though genetic patterns differ subtly between groups, the deeper similarities show how closely humanity is connected. Thanks to this shared heritage, small differences between populations can serve as powerful tools for unearthing discoveries that will help us all.
Pedersen, C. E. T., Lohmueller, K. E., Grarup, N., Bjerregaard, P., Hansen, T., Siegismund, H. R., Moltke, I., & Albrechtsen, A. (2016). The Effect of an Extreme and Prolonged Population Bottleneck on Patterns of Deleterious Variation: Insights from the Greenlandic Inuit. GENETICS, 205 (2): 787-801. DOI:10.1534/genetics.116.193821
Katie is a science writer at GSA. She did her PhD work on the evolutionary consequences of genetic conflict in fruit flies at the University of Georgia.
View all posts by Katie Pieper »Read more in
-
Early Career Leadership Spotlight: Julio Molina Pineda
We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Julio Molina Pineda Policy and Advocacy University of Arkansas Research Interest My research interests focus on using model organisms to genetically dissect complex traits related to human disease. My…
-
Early Career Leadership Spotlight: Peiwei Chen
We’re taking time to get to know the members of the GSA’s Early Career Scientist Committees. Join us to learn more about our early career scientist advocates. Peiwei Chen Accessibility Subcommittee California Institute of Technology Research Interest Far from a harmonious place, the genome is a battleground, where every bit of DNA fights for inheritance and…
-
#Dros23 GSA Poster Award winners
We are pleased to announce the GSA Poster Award winners from the 64th Annual Drosophila Research Conference! Undergraduate and graduate student members of the GSA were eligible for the awards, and a hard-working team of postdocs volunteered their time as judges. Congratulations to all! Undergraduate Students 1st Place: Sofia Karter Lopez, University of Toronto “Rab11 mediates E-cadherin recycling during…
-
Congratulations to the Fall 2022 DeLill Nasser Awardees!
GSA is pleased to announce the recipients of the DeLill Nasser Award for Professional Development in Genetics for Fall 2022! Given twice a year to graduate students and postdoctoral researchers, DeLill Nasser Awards support attendance at meetings and laboratory courses. The award is named in honor of DeLill Nasser, a long-time GSA supporter and National Science Foundation…
-
New editors join GENETICS, G3 editorial boards
Several new editors are joining the GSA Journals. We’re excited to welcome Ricardo Zayas to the GENETICS editorial board under the Molecular Genetics of Development section, and on the G3: Genes|Genomes|Genetics board, we welcome Polly Campbell, Kevin Vogel, Joe Parker, and Ricardo Mallarino. Ricardo Zayas Associate Editor Ricardo Zayas is a Professor of Biology at…
-
Worms and Flies Provide Key Clues to Medical Mystery
This article is part of a series of posts outlining the history and impact of research in experimental organisms. The series is developed in collaboration with the GSA Public Communications and Engagement Committee. By the time Bertrand Might was six months old, it was clear something was amiss. His muscles weren’t developing normally; he was…
-
Congratulations to the 2023 Early Career Leadership Program Cohort!
The Genetics Society of America (GSA) is excited to announce the latest cohort of student, postdoc, and early-career research leaders joining the Early Career Leadership Program. Participants receive training and mentoring while serving on committees charged with understanding the needs, interests, concerns, and challenges of early career scientist members of the GSA. As part of…
-
GSA LOCI: Local Outreach Community Initiatives @ GSA Conferences
Highlights: Local Outreach Community Initiatives (LOCI): The Genetics Society of America is committed to supporting the communities of the host cities of our conferences. This new year, we are excited to reconnect with our GSA community in meaningful ways within and beyond our existing programming. The GSA membership has created a caring and supportive environment…
-
New members of the GSA Board of Directors: 2023–2025
We are pleased to announce the election of five new leaders to the GSA Board of Directors: 2023 Vice President/2024 President Mariana Wolfner Distinguished Professor of Molecular Biology and Genetics and Stephen H. Weiss Presidential Fellow My research has focused on the genes and pathways that mediate sexual development and reproduction, primarily in Drosophila. From…
-
Lance David Miller: Lighting Your Own Fire by Finding the Right Resources
By Daniel J. Gironda In the Paths to Science Policy series, we talk to individuals who have a passion for science policy and are active in advocacy through their various roles and careers. The series aims to inform and guide early career scientists interested in science policy. This series is brought to you by the…
-
Graça Almeida-Porada: The Importance of Communication in a Technologically Advancing World
By Daniel J. Gironda In the Paths to Science Policy series, we talk to individuals who have a passion for science policy and are active in advocacy through their various roles and careers. The series aims to inform and guide early career scientists interested in science policy. This series is brought to you by the…