Published: 28-04-2023 07:54 | Updated: 28-04-2023 07:54

Genomes from 240 mammalian species explain human disease risks

Why is it that certain mammals have an exceptional sense of smell, some hibernate, and yet others, including humans, are predisposed to disease? In a major international research project where researchers at Karolinska Institutet participated, has surveyed and analysed the genomes of 240 different mammals. The results, now published in 11 articles in the journal Science, shows which regions have important functions in mammals.

Image of Professor Patrick Sullivan
Professor Patrick Sullivan at the Deparment of Medical Epidemiology and Biostatistics, and University of North Carolina at Chapel Hill. Photo: University of North Carolina at Chapel Hill

The studies show how the genomes of humans and other mammals have developed over the course of evolution, which mutations have led to specific characteristics in different species and which mutations can cause disease.

In a press release from Uppsala University, this large international project is described, which is jointly led by Uppsala University and the Broad Institute. More than 30 research teams, including researchers at Karolinska Institutet, have together surveyed and analysed the genomes of 240 mammal species. The results, now published in 11 articles in the journal Science, show how the genomes of humans and other mammals have developed in the course of evolution.

The human genome contains approximately 20,000 genes that constitute the code for manufacturing all the proteins in the body. The genome also contains instructions that direct where, when and how much of the proteins are produced. These parts of the genome, which are called regulatory elements, are much more difficult to identify than the parts that give rise to proteins. However, studying a great many mammals’ genomes makes it possible to figure out which parts of the genome are functionally important.

The hypothesis shared by the researchers behind the publications in Science has been that if a position in the genome has been preserved throughout 100 million years of evolution, it likely serves a function in all mammals. For the first time, they have been able to test this hypothesis on a large scale. By making a detailed survey and systematic comparison of the genomes of 240 mammals, the researchers have identified regions of the human genome which are likely regulatory elements and are significant for the correct functioning of the genome. Mutations in these can play an important role in the origin of diseases or in the distinctive features of mammal species.

The researchers identified more than three million important regulatory elements in the human genome, about half of which were previously unknown. They were also able to ascertain that at least 10 per cent of the genome is functional, ten times as much as the approximately one per cent that codes for proteins.

The 240 different mammals in the study vary widely in their characteristics, such as the acuteness of their sense of smell or the size of their brain. The researchers were able to find regions in the genomes that lead to differences in this type of traits and thereby create a picture of which mutations have steered the development of specific traits in different mammals.

Increased understanding of disease risk

The genomes of healthy and sick people are compared to understand which mutations lead to disease. Previous studies have identified thousands of genetic variants associated with an increased risk of different disorders. This produces a picture of the region in the genome that may be important, but does not yield an exact knowledge of which mutation causes the disease.

”By comparing the genomes of this large number of different mammals we have been able to identify those regions of the human genome that have been highly preserved during evolution, and therefore likely are functional. This information improves our possibilities to identify genetic variants which are increasing the risk for different disorders”,  says professor Patrick Sullivan, from the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet, and Department of Genetics and Psychiatry at the University of North Carolina at Chapel Hill, who is shared first author on the article which focuses on how the project’s data can contribute to knowledge about diseases.

”With the help of our new data about evolutionary conserved genetic positions, we have, for example, identified new genes that might be involved in the development of certain brain tumors in children and also genetic risk variants for schizophrenia”, Patrick Sullivan continues.

This work was supported in part by the National Institutes of Health (US), the Swedish Research Council (SWE), the Knut and Alice Wallenberg Foundation (SWE), and the National Science Foundation (US)..

Main publications

Leveraging base-pair mammalian constraint to understand genetic variation and human disease.
Sullivan PF, Meadows JRS, Gazal S, Phan BN, Li X, Genereux DP, Dong MX, Bianchi M, Andrews G, Sakthikumar S, Nordin J, Roy A, Christmas MJ, Marinescu VD, Wang C, Wallerman O, Xue J, Yao S, Sun Q, Szatkiewicz J, Wen J, Huckins LM, Lawler A, Keough KC, Zheng Z, Zeng J, Wray NR, Li Y, Johnson J, Chen J, , Paten B, Reilly SK, Hughes GM, Weng Z, Pollard KS, Pfenning AR, Forsberg-Nilsson K, Karlsson EK, Lindblad-Toh K, Andrews G, Armstrong JC, Bianchi M, Birren BW, Bredemeyer KR, Breit AM, Christmas MJ, Clawson H, Damas J, Di Palma F, Diekhans M, Dong MX, Eizirik E, Fan K, Fanter C, Foley NM, Forsberg-Nilsson K, Garcia CJ, Gatesy J, Gazal S, Genereux DP, Goodman L, Grimshaw J, Halsey MK, Harris AJ, Hickey G, Hiller M, Hindle AG, Hubley RM, Hughes GM, Johnson J, Juan D, Kaplow IM, Karlsson EK, Keough KC, Kirilenko B, Koepfli KP, Korstian JM, Kowalczyk A, Kozyrev SV, Lawler AJ, Lawless C, Lehmann T, Levesque DL, Lewin HA, Li X, Lind A, Lindblad-Toh K, Mackay-Smith A, Marinescu VD, Marques-Bonet T, Mason VC, Meadows JRS, Meyer WK, Moore JE, Moreira LR, Moreno-Santillan DD, Morrill KM, Muntané G, Murphy WJ, Navarro A, Nweeia M, Ortmann S, Osmanski A, Paten B, Paulat NS, Pfenning AR, Phan BN, Pollard KS, Pratt HE, Ray DA, Reilly SK, Rosen JR, Ruf I, Ryan L, Ryder OA, Sabeti PC, Schäffer DE, Serres A, Shapiro B, Smit AFA, Springer M, Srinivasan C, Steiner C, Storer JM, Sullivan KAM, Sullivan PF, Sundström E, Supple MA, Swofford R, Talbot JE, Teeling E, Turner-Maier J, Valenzuela A, Wagner F, Wallerman O, Wang C, Wang J, Weng Z, Wilder AP, Wirthlin ME, Xue JR, Zhang X
Science 2023 Apr;380(6643):eabn2937

The functional and evolutionary impacts of human-specific deletions in conserved elements.
Xue JR, Mackay-Smith A, Mouri K, Garcia MF, Dong MX, Akers JF, Noble M, Li X, , Lindblad-Toh K, Karlsson EK, Noonan JP, Capellini TD, Brennand KJ, Tewhey R, Sabeti PC, Reilly SK, Andrews G, Armstrong JC, Bianchi M, Birren BW, Bredemeyer KR, Breit AM, Christmas MJ, Clawson H, Damas J, Di Palma F, Diekhans M, Dong MX, Eizirik E, Fan K, Fanter C, Foley NM, Forsberg-Nilsson K, Garcia CJ, Gatesy J, Gazal S, Genereux DP, Goodman L, Grimshaw J, Halsey MK, Harris AJ, Hickey G, Hiller M, Hindle AG, Hubley RM, Hughes GM, Johnson J, Juan D, Kaplow IM, Karlsson EK, Keough KC, Kirilenko B, Koepfli KP, Korstian JM, Kowalczyk A, Kozyrev SV, Lawler AJ, Lawless C, Lehmann T, Levesque DL, Lewin HA, Li X, Lind A, Lindblad-Toh K, Mackay-Smith A, Marinescu VD, Marques-Bonet T, Mason VC, Meadows JRS, Meyer WK, Moore JE, Moreira LR, Moreno-Santillan DD, Morrill KM, Muntané G, Murphy WJ, Navarro A, Nweeia M, Ortmann S, Osmanski A, Paten B, Paulat NS, Pfenning AR, Phan BN, Pollard KS, Pratt HE, Ray DA, Reilly SK, Rosen JR, Ruf I, Ryan L, Ryder OA, Sabeti PC, Schäffer DE, Serres A, Shapiro B, Smit AFA, Springer M, Srinivasan C, Steiner C, Storer JM, Sullivan KAM, Sullivan PF, Sundström E, Supple MA, Swofford R, Talbot JE, Teeling E, Turner-Maier J, Valenzuela A, Wagner F, Wallerman O, Wang C, Wang J, Weng Z, Wilder AP, Wirthlin ME, Xue JR, Zhang X
Science 2023 Apr;380(6643):eabn2253

Evolutionary constraint and innovation across hundreds of placental mammals.
Christmas MJ, Kaplow IM, Genereux DP, Dong MX, Hughes GM, Li X, Sullivan PF, Hindle AG, Andrews G, Armstrong JC, Bianchi M, Breit AM, Diekhans M, Fanter C, Foley NM, Goodman DB, Goodman L, Keough KC, Kirilenko B, Kowalczyk A, Lawless C, Lind AL, Meadows JRS, Moreira LR, Redlich RW, Ryan L, Swofford R, Valenzuela A, Wagner F, Wallerman O, Brown AR, Damas J, Fan K, Gatesy J, Grimshaw J, Johnson J, Kozyrev SV, Lawler AJ, Marinescu VD, Morrill KM, Osmanski A, Paulat NS, Phan BN, Reilly SK, Schäffer DE, Steiner C, Supple MA, Wilder AP, Wirthlin ME, Xue JR, , Birren BW, Gazal S, Hubley RM, Koepfli KP, Marques-Bonet T, Meyer WK, Nweeia M, Sabeti PC, Shapiro B, Smit AFA, Springer MS, Teeling EC, Weng Z, Hiller M, Levesque DL, Lewin HA, Murphy WJ, Navarro A, Paten B, Pollard KS, Ray DA, Ruf I, Ryder OA, Pfenning AR, Lindblad-Toh K, Karlsson EK, Andrews G, Armstrong JC, Bianchi M, Birren BW, Bredemeyer KR, Breit AM, Christmas MJ, Clawson H, Damas J, Di Palma F, Diekhans M, Dong MX, Eizirik E, Fan K, Fanter C, Foley NM, Forsberg-Nilsson K, Garcia CJ, Gatesy J, Gazal S, Genereux DP, Goodman L, Grimshaw J, Halsey MK, Harris AJ, Hickey G, Hiller M, Hindle AG, Hubley RM, Hughes GM, Johnson J, Juan D, Kaplow IM, Karlsson EK, Keough KC, Kirilenko B, Koepfli KP, Korstian JM, Kowalczyk A, Kozyrev SV, Lawler AJ, Lawless C, Lehmann T, Levesque DL, Lewin HA, Li X, Lind A, Lindblad-Toh K, Mackay-Smith A, Marinescu VD, Marques-Bonet T, Mason VC, Meadows JRS, Meyer WK, Moore JE, Moreira LR, Moreno-Santillan DD, Morrill KM, Muntané G, Murphy WJ, Navarro A, Nweeia M, Ortmann S, Osmanski A, Paten B, Paulat NS, Pfenning AR, Phan BN, Pollard KS, Pratt HE, Ray DA, Reilly SK, Rosen JR, Ruf I, Ryan L, Ryder OA, Sabeti PC, Schäffer DE, Serres A, Shapiro B, Smit AFA, Springer M, Srinivasan C, Steiner C, Storer JM, Sullivan KAM, Sullivan PF, Sundström E, Supple MA, Swofford R, Talbot JE, Teeling E, Turner-Maier J, Valenzuela A, Wagner F, Wallerman O, Wang C, Wang J, Weng Z, Wilder AP, Wirthlin ME, Xue JR, Zhang X
Science 2023 Apr;380(6643):eabn3943