Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Genome-Based Sexing Provides Clues about Behavior and Social Structure in the Woolly Mammoth
Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.ORCID iD: 0000-0001-9350-1987
Show others and affiliations
2017 (English)In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 27, no 22, p. 3505-3510.e3Article in journal (Refereed) Published
Abstract [en]

While present-day taxa are valuable proxies for understanding the biology of extinct species, it is also crucial to examine physical remains in order to obtain a more comprehensive view of their behavior, social structure, and life histories [1, 2]. For example, information on demographic parameters such as age distribution and sex ratios in fossil assemblages can be used to accurately infer socioecological patterns (e.g., [3]). Here we use genomic data to determine the sex of 98 woolly mammoth (Mammuthus primigenius) specimens in order to infer social and behavioral patterns in the last 60,000 years of the species' existence. We report a significant excess of males among the identified samples (69% versus 31%; p < 0.0002). We argue that this male bias among mammoth remains is best explained by males more often being caught in natural traps that favor preservation. Wehypothesize that this is a consequence of social structure in proboscideans, which is characterized by matriarchal hierarchy and sex segregation. Without the experience associated with living in a matriarchal family group, or a bachelor group with an experienced bull, young or solitary males may have been more prone to die in natural traps where good preservation is more likely.

Place, publisher, year, edition, pages
2017. Vol. 27, no 22, p. 3505-3510.e3
Keywords [en]
Mammuthus primigenius, sex ratio, sex bias, behaviour, ancient DNA, paleogenetics, mortality
National Category
Evolutionary Biology
Research subject
Systematic Zoology
Identifiers
URN: urn:nbn:se:su:diva-149646DOI: 10.1016/j.cub.2017.09.064ISI: 000415815800028PubMedID: 29103934OAI: oai:DiVA.org:su-149646DiVA, id: diva2:1163635
Available from: 2017-12-07 Created: 2017-12-07 Last updated: 2017-12-21Bibliographically approved
In thesis
1. Genomic analysis of the process leading up to the extinction of the woolly mammoth
Open this publication in new window or tab >>Genomic analysis of the process leading up to the extinction of the woolly mammoth
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Species worldwide are subject to contractions in both abundance and geographical range, and their persistence in a changing environment may thus depend on the ability to survive in small and fragmented populations. Despite the urgent need to understand how extinction works, our knowledge of pre-extinction genetic processes is limited because techniques allowing population and conservation genomics to be studied in wild threatened populations have become available only recently. In this thesis, I used the last surviving population of the woolly mammoth (Mammuthus primigenius) as a model for studying pre-extinction population dynamics. I used ancient DNA as a tool to study microevolutionary processes in real time, analysing genetic changes in response to environmental shifts at the end of the last Ice Age and exploring impacts of genetic drift and inbreeding as woolly mammoths became isolated on Wrangel Island and survived for 6000 years at small population size. Using mitochondrial genomes, I found evidence of a founder effect that decreased the maternal diversity to a single lineage at the time when mammoths became trapped on Wrangel Island (~10,500 years ago). Moreover, a two- to three-fold higher mitochondrial mutation rate in Holocene and a fixed, potentially detrimental mutation in the ATP6 gene encoding for one of the key enzymes of the oxidative phosphorylation pathway, is consistent with the hypothesis that selection is less effective in removing deleterious mutations in small populations. A loss of diversity was also observed in an immunity gene that belongs to the major histocompatibility complex (MHC), even though the MHC is considered to be under balancing selection. Low-coverage genomic data was analysed in order to estimate endogenous DNA content and molecular sex of the mammoth samples. The observation of a male bias (69%) in the sex ratio led to the conclusion that male mammoths were more likely to die in a way that ensured good preservation. Another potential way of getting information about life history strategies of extinct species, which was explored here, is by measuring testosterone levels in mammoth hair shafts in connection with molecular sex inference. Finally, given that previous estimates have suggested a very small Holocene effective population size on Wrangel Island and thus that the population may have been too small to avoid genome erosion, four mammoths were sequenced to a high coverage in order to look for genomic consequences of small population size. When compared to mammoths from the Pleistocene mainland population, Wrangel Island mammoths had lower levels of genome-wide diversity and had a higher proportion of their genomes allocated in runs of homozygosity, which are large fragments completely depleted of diversity. Importantly, genome erosion appears to have accelerated in the last ten generations before the extinction, resulting in the last known woolly mammoth having almost 40% of its genome without any genetic diversity. Overall, these results highlight how genetic drift and inbreeding triggered genomic deterioration in the last surviving woolly mammoth population. Although Wrangel Island was a refugium, where mammoths survived for thousands of years after the last Ice Age, and the causal factors of the final extinction are not yet clear, isolation and small population size without any possibility of new gene flow may have contributed to reduced fitness, and thus to extinction. 

Place, publisher, year, edition, pages
Stockholm: Department of Zoology, Stockholm University, 2018
Keywords
woolly mammoth, Mammuthus primigenius, extinction, Wrangel Island, ancient DNA, palaeogenetics, population genetics, genomics, genomic erosion, genetic drift, inbreeding, population size
National Category
Evolutionary Biology
Research subject
Systematic Zoology
Identifiers
urn:nbn:se:su:diva-149655 (URN)978-91-7797-089-7 (ISBN)978-91-7797-090-3 (ISBN)
Public defence
2018-02-13, Vivi Täckholmssalen, NPQ-huset, Svante Arrhenius väg 20, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.

Available from: 2018-01-19 Created: 2017-12-11 Last updated: 2018-01-11Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Pečnerová, Patrícia
By organisation
Department of Zoology
In the same journal
Current Biology
Evolutionary Biology

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 39 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf