scholarly journals The evolutionary history of human spindle genes includes back-and-forth gene flow with Neandertals

2021 ◽  
Author(s):  
Stéphane Peyrégne ◽  
Janet Kelso ◽  
Benjamin Marco Peter ◽  
Svante Pääbo
Keyword(s):  
Gene Flow ◽  
Evolutionary History ◽  
Common Ancestor ◽  
Modern Human ◽  
Modern Humans ◽  
Ancestral Gene ◽  
Cytoskeletal Structure ◽  
Spindle Apparatus ◽  
History Of ◽  
Segregation Of Chromosomes

Proteins associated with the spindle apparatus, a cytoskeletal structure that ensures the proper segregation of chromosomes during cell division, experienced an unusual number of amino acid substitutions in modern humans after the split from the ancestors of Neandertals and Denisovans. Here, we analyze the history of these substitutions and show that some of the genes in which they occur may have been targets of positive selection. We also find that the two changes in the kinetochore scaffold 1 (KNL1) protein, previously believed to be specific to modern humans, were present in some Neandertals. We show that the KNL1 gene of these Neandertals shared a common ancestor with present-day Africans about 200,000 years ago due to gene flow from the ancestors (or relatives) of modern humans into Neandertals. Subsequently, some non-Africans inherited this modern human-like gene variant from Neandertals, but none inherited the ancestral gene variants. These results add to the growing evidence of early contacts between modern humans and archaic groups in Eurasia and illustrate the intricate relationships among these groups.

2. Finding our place

2019 ◽  
pp. 7-23
Author(s):  
Bernard Wood
Keyword(s):  
Molecular Biology ◽  
Human Evolution ◽  
Scientific Method ◽  
Common Ancestor ◽  
Natural World ◽  
Modern Human ◽  
Human Origins ◽  
Modern Humans ◽  
History Of ◽  
The Common

When did the process of using reason to try and understand human origins begin, and how did it develop? When was the scientific method first applied to the study of human evolution? ‘Finding our place’ begins by reviewing the history of how first philosophers and then scientists came to realize that modern humans are part of the natural world. It then explains why, using advances in molecular biology, scientists think chimpanzees and bonobos are more closely related to modern humans than they are to gorillas, and why they think the common ancestor of the chimpanzee/bonobo and modern human clades lived between six and eight million years ago.

scholarly journals The evolutionary history of Neandertal and Denisovan Y chromosomes

2020 ◽  
Author(s):  
Martin Petr ◽  
Mateja Hajdinjak ◽  
Qiaomei Fu ◽  
Elena Essel ◽  
Hélène Rougier ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Evolutionary History ◽  
Genetic Load ◽  
Modern Human ◽  
Gene Pools ◽  
Human History ◽  
Effective Population ◽  
Modern Humans ◽  
Y Chromosomes ◽  
History Of

AbstractAncient DNA has allowed the study of various aspects of human history in unprecedented detail. However, because the majority of archaic human specimens preserved well enough for genome sequencing have been female, comprehensive studies of Y chromosomes of Denisovans and Neandertals have not yet been possible. Here we present sequences of the first Denisovan Y chromosomes (Denisova 4 and Denisova 8), as well as the Y chromosomes of three late Neandertals (Spy 94a, Mezmaiskaya 2 and El Sidrón 1253). We find that the Denisovan Y chromosomes split around 700 thousand years ago (kya) from a lineage shared by Neandertal and modern human Y chromosomes, which diverged from each other around 370 kya. The phylogenetic relationships of archaic and modern human Y chromosomes therefore differ from population relationships inferred from their autosomal genomes, and mirror the relationships observed on the level of mitochondrial DNA. This provides strong evidence that gene flow from an early lineage related to modern humans resulted in the replacement of both the mitochondrial and Y chromosomal gene pools in late Neandertals. Although unlikely under neutrality, we show that this replacement is plausible if the low effective population size of Neandertals resulted in an increased genetic load in their Y chromosomes and mitochondrial DNA relative to modern humans.

scholarly journals Molecular evolutionary analysis of human primary microcephaly genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nashaiman Pervaiz ◽  
Hongen Kang ◽  
Yiming Bao ◽  
Amir Ali Abbasi
Keyword(s):  
Evolutionary History ◽  
Genetic Basis ◽  
Brain Size ◽  
Primate Species ◽  
Evolutionary Analysis ◽  
Australopithecus Afarensis ◽  
Primary Microcephaly ◽  
Modern Humans ◽  
History Of ◽  
The Brain

Abstract Background There has been a rapid increase in the brain size relative to body size during mammalian evolutionary history. In particular, the enlarged and globular brain is the most distinctive anatomical feature of modern humans that set us apart from other extinct and extant primate species. Genetic basis of large brain size in modern humans has largely remained enigmatic. Genes associated with the pathological reduction of brain size (primary microcephaly-MCPH) have the characteristics and functions to be considered ideal candidates to unravel the genetic basis of evolutionary enlargement of human brain size. For instance, the brain size of microcephaly patients is similar to the brain size of Pan troglodyte and the very early hominids like the Sahelanthropus tchadensis and Australopithecus afarensis. Results The present study investigates the molecular evolutionary history of subset of autosomal recessive primary microcephaly (MCPH) genes; CEP135, ZNF335, PHC1, SASS6, CDK6, MFSD2A, CIT, and KIF14 across 48 mammalian species. Codon based substitutions site analysis indicated that ZNF335, SASS6, CIT, and KIF14 have experienced positive selection in eutherian evolutionary history. Estimation of divergent selection pressure revealed that almost all of the MCPH genes analyzed in the present study have maintained their functions throughout the history of placental mammals. Contrary to our expectations, human-specific adoptive evolution was not detected for any of the MCPH genes analyzed in the present study. Conclusion Based on these data it can be inferred that protein-coding sequence of MCPH genes might not be the sole determinant of increase in relative brain size during primate evolutionary history.

scholarly journals Evolutionary history of dimethylsulfoniopropionate (DMSP) demethylation enzyme DmdA in marine bacteria

2019 ◽  
Author(s):  
Laura Hernández ◽  
Alberto Vicens ◽  
Luis Enrique Eguiarte ◽  
Valeria Souza ◽  
Valerie De Anda ◽  
...  
Keyword(s):  
Gene Family ◽  
Evolutionary History ◽  
Common Ancestor ◽  
Functional Divergence ◽  
Gene Families ◽  
Recent Common Ancestor ◽  
Common Ancestry ◽  
Demethylation Pathway ◽  
History Of ◽  
New Gene

ABSTRACTDimethylsulfoniopropionate (DMSP), an osmolyte produced by oceanic phytoplankton, is predominantly degraded by bacteria belonging to the Roseobacter lineage and other marine Alphaproteobacteria via DMSP-dependent demethylase A protein (DmdA). To date, the evolutionary history of DmdA gene family is unclear. Some studies indicate a common ancestry between DmdA and GcvT gene families and a co-evolution between Roseobacter and the DMSP-producing-phytoplankton around 250 million years ago (Mya). In this work, we analyzed the evolution of DmdA under three possible evolutionary scenarios: 1) a recent common ancestor of DmdA and GcvT, 2) a coevolution between Roseobacter and the DMSP-producing-phytoplankton, and 3) pre-adapted enzymes to DMSP prior to Roseobacter origin. Our analyses indicate that DmdA is a new gene family originated from GcvT genes by duplication and functional divergence driven by positive selection before a coevolution between Roseobacter and phytoplankton. Our data suggest that Roseobacter acquired dmdA by horizontal gene transfer prior to exposition to an environment with higher DMSP. Here, we propose that the ancestor that carried the DMSP demethylation pathway genes evolved in the Archean, and was exposed to a higher concentration of DMSP in a sulfur rich atmosphere and anoxic ocean, compared to recent Roseobacter ecoparalogs (copies performing the same function under different conditions), which should be adapted to lower concentrations of DMSP.

scholarly journals Denisovan ancestry and population history of early East Asians

2020 ◽  
Author(s):  
Diyendo Massilani ◽  
Laurits Skov ◽  
Mateja Hajdinjak ◽  
Byambaa Gunchinsuren ◽  
Damdinsuren Tseveendorj ◽  
...  
Keyword(s):  
Gene Flow ◽  
Human Population ◽  
Modern Human ◽  
Population History ◽  
East Asians ◽  
Aboriginal Australians ◽  
North East ◽  
History Of ◽  
Female Member ◽  
Admixture Event

AbstractWe present analyses of the genome of a ~34,000-year-old hominin skull cap discovered in the Salkhit Valley in North East Mongolia. We show that this individual was a female member of a modern human population that, following the split between East and West Eurasians, experienced substantial gene flow from West Eurasians. Both she and a 40,000-year-old individual from Tianyuan outside Beijing carried genomic segments of Denisovan ancestry. These segments derive from the same Denisovan admixture event(s) that contributed to present-day mainland Asians but are distinct from the Denisovan DNA segments in present-day Papuans and Aboriginal Australians.

Phylogenetic evidence for independent origins of GDF1 and GDF3 genes in amphibians and mammals

2018 ◽  
Author(s):  
Juan C. Opazo ◽  
Kattina Zavala
Keyword(s):  
Growth Factor ◽  
Early Development ◽  
Evolutionary History ◽  
Transforming Growth Factor ◽  
Ancestral Gene ◽  
Differentiation Factors ◽  
Duplication Events ◽  
Independent Duplication ◽  
History Of ◽  
Early Developmental

AbstractGrowth differentiation factors 1 (GDF1) and 3 (GDF3) are members of the transforming growth factor superfamily (TGF-β) that is involved in fundamental early-developmental processes that are conserved across vertebrates. The evolutionary history of these genes is still under debate due to ambiguous definitions of homologous relationships among vertebrates. Thus, the goal of this study was to unravel the evolution of the GDF1 and GDF3 genes of vertebrates, emphasizing the understanding of homologous relationships and their evolutionary origin. Surprisingly, our results revealed that the GDF1 and GDF3 genes found in amphibians and mammals are the products of independent duplication events of an ancestral gene in the ancestor of each of these lineages. The main implication of this result is that the GDF1 and GDF3 genes of amphibians and mammals are not 1:1 orthologs. In other words, genes that participate in fundamental processes during early development have been reinvented two independent times during the evolutionary history of tetrapods.

scholarly journals Denisovan ancestry and population history of early East Asians

Science ◽  
2020 ◽  
Vol 370 (6516) ◽  
pp. 579-583
Author(s):  
Diyendo Massilani ◽  
Laurits Skov ◽  
Mateja Hajdinjak ◽  
Byambaa Gunchinsuren ◽  
Damdinsuren Tseveendorj ◽  
...  
Keyword(s):  
Gene Flow ◽  
Human Population ◽  
Modern Human ◽  
Population History ◽  
East Asians ◽  
Aboriginal Australians ◽  
History Of ◽  
East And West ◽  
Female Member ◽  
Admixture Event

We present analyses of the genome of a ~34,000-year-old hominin skull cap discovered in the Salkhit Valley in northeastern Mongolia. We show that this individual was a female member of a modern human population that, following the split between East and West Eurasians, experienced substantial gene flow from West Eurasians. Both she and a 40,000-year-old individual from Tianyuan outside Beijing carried genomic segments of Denisovan ancestry. These segments derive from the same Denisovan admixture event(s) that contributed to present-day mainland Asians but are distinct from the Denisovan DNA segments in present-day Papuans and Aboriginal Australians.

scholarly journals The origin, current diversity and future conservation of the modern lion ( Panthera leo )

2006 ◽  
Vol 273 (1598) ◽  
pp. 2119-2125 ◽  
Author(s):  
Ross Barnett ◽  
Nobuyuki Yamaguchi ◽  
Ian Barnes ◽  
Alan Cooper
Keyword(s):  
Evolutionary History ◽  
Mitochondrial Control Region ◽  
Modern Human ◽  
Conservation Strategies ◽  
African Origin ◽  
Continental Scale ◽  
History Of ◽  
Physical Barriers ◽  
Geographic Populations ◽  
Sub Saharan

Understanding the phylogeographic processes affecting endangered species is crucial both to interpreting their evolutionary history and to the establishment of conservation strategies. Lions provide a key opportunity to explore such processes; however, a lack of genetic diversity and shortage of suitable samples has until now hindered such investigation. We used mitochondrial control region DNA (mtDNA) sequences to investigate the phylogeographic history of modern lions, using samples from across their entire range. We find the sub-Saharan African lions are basal among modern lions, supporting a single African origin model of modern lion evolution, equivalent to the ‘recent African origin’ model of modern human evolution. We also find the greatest variety of mtDNA haplotypes in the centre of Africa, which may be due to the distribution of physical barriers and continental-scale habitat changes caused by Pleistocene glacial oscillations. Our results suggest that the modern lion may currently consist of three geographic populations on the basis of their recent evolutionary history: North African–Asian, southern African and middle African. Future conservation strategies should take these evolutionary subdivisions into consideration.

Sign in / Sign up

Export Citation Format

Share Document