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Marsupials and Eutherians reunited: genetic evidence for the Theria hypothesis of mammalian evolution

journal contribution
posted on 2023-05-16, 13:07 authored by Killian, JK, Buckley, TR, Niall Stewart, Munday, BL, Jirtle, RL
The three living monophyletic divisions of Class Mammalia are the Prototheria (monotremes), Metatheria (marsupials), and Eutheria ('placental' mammals). Determining the sister relationships among these three groups is the most fundamental question in mammalian evolution. Phylogenetic comparison of these mammals by either anatomy or mitochondrial DNA has resulted in two conflicting hypotheses, Theria and Marsupionta, and has fueled a "genes versus morphology" controversy. We have cloned and analyzed a large nuclear gene, the mannose 6-phosphate/ insulin-like growth factor II receptor (M6P/IGF2R), from representatives of all three mammalian groups, including platypus, echidna, opossum, wallaby, hedgehog, mouse, rat, rabbit, cow, pig, bat, tree shrew, colugo, ringtail lemur, and human. Statistical analysis of this nuclear gene unambiguously supports the morphology-based Theria hypothesis that excludes monotremes from a clade of marsupials and eutherians. The M6P/IGF2R was also able to resolve the finer structure of the eutherian mammalian family tree. In particular, our analyses support sister group relationships between lagomorphs and rodents, and between the primates and Dermoptera. Statistical support for the grouping of the hedgehog with Feruungulata and Chiroptera was also strong.

History

Publication title

Mammalian Genome

Volume

12

Issue

7

Pagination

513-517

ISSN

0938-8990

Department/School

School of Health Sciences

Publisher

Springer-Verlag

Place of publication

United States of America

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the environmental sciences

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