<i>Australopithecus sediba</i>
            at 1.977 Ma and Implications for the Origins of the Genus
            <i>Homo</i>

Pickering, Robyn; Dirks, Paul H.G.M.; Jinnah, Zubair; Ruiter, Darryl J. de; Churchill, Steven E.; Herries, Andy I.R.; Woodhead, Jon; Hellström, John; Berger, Lee R.

doi:10.1126/science.1203697

Cited by 181 publications

(128 citation statements)

References 58 publications

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“…In 2010, Berger and co-workers [11,40] reported the discovery of 1.97 Ma fossil hominins from Malapa, South Africa. These fossils have a unique combination of morphological features, some of which are shared with the australopiths and others with early Homo.…”

Section: Resultsmentioning

confidence: 99%

Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships

et al. 2015

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The phylogenetic relationships of several hominin species remain controversial. Two methodological issues contribute to the uncertainty-use of partial, inconsistent datasets and reliance on phylogenetic methods that are ill-suited to testing competing hypotheses. Here, we report a study designed to overcome these issues. We first compiled a supermatrix of craniodental characters for all widely accepted hominin species. We then took advantage of recently developed Bayesian methods for building trees of serially sampled tips to test among hypotheses that have been put forward in three of the most important current debates in hominin phylogeneticsthe relationship between Australopithecus sediba and Homo, the taxonomic status of the Dmanisi hominins, and the place of the so-called hobbit fossils from Flores, Indonesia, in the hominin tree. Based on our results, several published hypotheses can be statistically rejected. For example, the data do not support the claim that Dmanisi hominins and all other early Homo specimens represent a single species, nor that the hobbit fossils are the remains of small-bodied modern humans, one of whom had Down syndrome. More broadly, our study provides a new baseline dataset for future work on hominin phylogeny and illustrates the promise of Bayesian approaches for understanding hominin phylogenetic relationships.

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Section: Resultsmentioning

confidence: 99%

Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships

et al. 2015

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“…Even with as broad an estimation as ϳ1 to 3 Ma, this places the divergence of the B2 clade in the ballpark of the estimated appearance of the genus Homo (2.3 to 2.4 Ma) (60) and provides yet another intriguing temporal link between human specialization and E. coli pathogenicity.…”

Section: Discussionmentioning

confidence: 99%

Chemoreceptor Gene Loss and Acquisition via Horizontal Gene Transfer in Escherichia coli

2013

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Ridge, Tennessee, USA b Chemotaxis allows bacteria to more efficiently colonize optimal microhabitats within their larger environment. Chemotaxis in Escherichia coli is the best-studied model system, and a large number of E. coli strains have been sequenced. The Escherichia/ Shigella genus encompasses a great variety of commensal and pathogenic strains, but the role of chemotaxis in their association with the host remains poorly understood. Here we show that the core chemotaxis genes are lost in many, but not all, nonmotile strains but are well preserved in all motile strains. The genes encoding the Tar, Tsr, and Aer chemoreceptors, which mediate chemotaxis to a broad spectrum of chemical and physical cues, are also nearly uniformly conserved in motile strains. In contrast, the clade of extraintestinal pathogenic E. coli strains apparently underwent an ancestral loss of Trg and Tap chemoreceptors, which sense sugars, dipeptides, and pyrimidines. The broad range of time estimated for the loss of these genes (1 to 3 million years ago) corresponds to the appearance of the genus Homo. Escherichia coli strains are ubiquitous colonizers of the intestines of mammals and birds (1). There are several highly adapted E. coli clones that have acquired virulence traits and cause a broad spectrum of disease, including enteric/diarrheal disease, urinary tract infections (UTIs), and sepsis/meningitis (2). Depending on the site of infection, pathogenic strains are classified as intestinal E. coli (IPEC) or extraintestinal pathogenic E. coli (ExPEC), and distinct pathotypes (based on clinical manifestation) are recognized within both categories. The most common ExPEC pathotypes include uropathogenic E. coli (UPEC), meningitis-associated E. coli (MNEC), and avian-pathogenic E. coli (APEC) (2, 3). Motility was shown to be important for the colonization of both commensal and pathogenic E. coli strains, as well as for the pathogenesis of the latter (4, 5): however, the exact role of motility and the underlying chemotaxis system in these processes remain poorly understood. The molecular machinery that controls chemotaxis in E. coli has been the subject of intensive investigation (6, 7). Its components include chemoreceptors, also known as methyl-accepting chemotaxis proteins (MCPs), a histidine kinase (CheA), an adaptor protein (CheW), a methyltransferase (CheR), and a methylesterase (CheB), as well as a response regulator (CheY) and its phosphatase (CheZ). E. coli has five chemoreceptors. Tsr mediates attractant responses to serine and quorum autoinducer AI-2 (8, 9), as well as responses to oxygen, redox, and oxidizable substrates (10, 11). It was also recently shown to mediate taxis to 3,4-dihydroxymandelic acid, a metabolite of norepinephrine that is produced by human cells (Mike Manson, personal communication). Tar mediates attractant responses to aspartate and maltose (9, 12) and negative responses to metal ions (13). Trg mediates attractant responses to ribose and galactose (14), and Tap mediates attractant responses to di...

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“…Rejecting the presence of pre-1.9 Ma specimens such as AL 666-1 and UR 501, as well as the Omo material (Berger, 2012), they argued that the Malapa specimens, dating to 1.977 (Pickering et al, 2011), predate any actual "uncontested" Homo specimens. Further, they proposed that the Malapa sample of A. sediba likely represents a late-surviving population of a species that must have been much older and was ancestral to…”

Section: In a Similar Vein Berger And Colleagues Have Proposed The Smentioning

confidence: 99%

“…African species A. sediba as a likely candidate ancestor for Homo (Berger, 2012;Berger et al, 2010;de Ruiter, Churchill, Hawks, & Berger, 2015;Hawks, & Berger, 2017;Pickering et al, 2011). Rejecting the presence of pre-1.9 Ma specimens such as AL 666-1 and UR 501, as well as the Omo material (Berger, 2012), they argued that the Malapa specimens, dating to 1.977 (Pickering et al, 2011), predate any actual "uncontested" Homo specimens.…”

Section: In a Similar Vein Berger And Colleagues Have Proposed The Smentioning

confidence: 99%

EarlyHomoand the role of the genus in paleoanthropology

Villmoare

2018

American J Phys Anthropol

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The history of the discovery of early fossils attributed to the genus Homo has been contentious, with scholars disagreeing over the generic assignment of fossils proposed as members of our genus. In this manuscript I review the history of discovery and debate over early Homo and evaluate the various taxonomic hypotheses for the genus. To get a sense of how hominin taxonomy compares to taxonomic practice outside paleoanthropology, I compare the diversity of Homo to genera in other vertebrate clades. Finally, I propose a taxonomic model that hews closely to current models for hominin phylogeny and is consistent with taxonomic practice across evolutionary biology. K E Y W O R D Searly Homo, genus, taxonomy | I N TR ODU C TI ONThe recent discovery of hominin fossils proposed as candidates for early members of the genus Homo (Berger et al., 2010;Leakey et al., 2012;Villmoare et al., 2015) has renewed debate on the taxonomy of our genus (Anton, Potts, & Aiello, 2014;Berger et al., 2012;Collard & Wood, 2015; Hawks et al., 2015;Kimbel & Villmoare, 2016;Schwartz & Tattersall, 2015). Here I review the history of discovery and debate for early members of our genus, and follow with a discussion of how the taxonomic rank of genus has been, and might be, applied to the human lineage. have now, as it appears to me, satisfactorily shown that not only in its general, but equally so in its particular characters, has the fossil under consideration the closest affinity to the apes" (King, 1864, pp. 96-97).In his 1863 lecture he proposed the taxonomic assignment "Homo Neanderthalensis" (sic), out of a sense of conservatism (largely based on the absence of preserved facial anatomy), but in 1864, in his published analysis of the vault, he reconsidered: "In that paper I called the fossil by the name Homo Neanderthalensis; but I now feel strongly inclined to believe that it is not only specifically but generically distinct from Man" (King, 1864, p. 96).However, the practice of applying the generic name Homo for newly discovered hominin fossils from Europe was largely retained (Wood, 2000) so that by 1907, when a hominin jaw was discovered in sand mines outside the village of Mauer, Germany, the species was designated H. heidelbergensis (Schoetensack, 1908) without controversy. The generic assignment was based largely on the human-like characteristics of the dentition, even though the lack of a chin and overall robusticity clearly placed the jaw outside the limits of known human variation (Harvati, 2007;MacCurdy, 1909;Smith Woodward, 1925). Subsequent attempts to transfer the specimen to the genus Paleoanthropus (Bonarelli, 1909;McKown & Keith, 1939) were not adopted by the scientific community. Discoverers felt relatively free to assign specific distinction to new discoveries, leading to the proliferation of fossil species in Homo in the late 19th and early 20th centuries -for example, H. mousteriensis, H. primigenius, H. antiquus, H. spelaeus, H. rhodesiensis, H. soloensis, and so forth. (Harvati, 2007;MacCurdy, 1908MacCurdy, ,...

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Australopithecus sediba at 1.977 Ma and Implications for the Origins of the Genus Homo

Cited by 181 publications

References 58 publications

Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships

Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships

Chemoreceptor Gene Loss and Acquisition via Horizontal Gene Transfer in Escherichia coli

EarlyHomoand the role of the genus in paleoanthropology

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