early-human-ancestors-used-their-hands-like-modern-humans

Early Human Ancestors Used Their Hands Like Modern Humans

New research suggests pre-Homo human ancestral species, such as Australopithecus africanus, used human-like hand postures much earlier than was previously thought.

Anthropologists from the University of Kent, working with researchers from University College London, the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany) and the Vienna University of Technology (Austria), have produced the first research findings to support archaeological evidence for stone tool use among fossil australopiths 3-2 million years ago. The distinctly human ability for forceful precision (e.g. when turning a key) and power “squeeze” gripping (e.g. when using a hammer) is linked to two key evolutionary transitions in hand use: a reduction in arboreal climbing and the manufacture and use of stone tools. However, it is unclear when these locomotory and manipulative transitions occurred.

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Current Nutrition Labeling is Hard to Digest

Current government-mandated nutrition labeling is ineffective in improving nutrition, but there is a better system available, according to a study by McGill University researchers published in the December issue of the Annals of the New York Academy of Sciences.

The researchers compared four different labeling systems and found that the Nutrition Facts label currently required on most food products in the US and Canada was least useable. That label, which lists the percent daily value of several nutrients, took more time to understand and led to nutrition choices hardly different from chance. Another label type, NuVal, enabled quick and nutritious choices. NuVal is a shelf sticker used in some American food markets, which indicates the overall nutritional value of each food item with a number from 1-100.

NuVal scores are calculated by nutrition experts at several universities, including Yale, Harvard, and Northwestern, and emphasize both the positive and negative aspects of each food. By reducing nutritional content to a single number, NuVal labels resolve nutrition conflicts.

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Which ‘letters’ in the human genome are functionally important?

There are 3 billion letters in the human genome, and scientists have endlessly debated how many of them serve a functional purpose. There are those letters that encode genes, our hereditary information, and those that provide instructions about how cells can use the genes. But those sequences are written with a comparative few of the vast number of DNA letters. Scientists have long debated how much of, or even if, the rest of our genome does anything, some going so far as to designate the part not devoted to encoding proteins as “junk DNA.”

“In model organisms, like yeast or flies, scientists often generate mutations to determine which letters in a DNA sequence are needed for a particular gene to function,” explains CSHL Professor Adam Siepel. “We can’t do that with humans. But when you think about it, nature has been doing a similar experiment on a very large scale as species evolve. Mutations occur across the genome at random, but important letters are retained by natural selection, while the rest are free to change with no adverse consequence to the organism.” It was this idea that became the basis of their analysis, but it alone wasn’t enough. “Massive research consortia, like the ENCODE Project, have provided the scientific community with a trove of information about genomic function over the last few years,” says Siepel. “Other groups have sequenced large numbers of humans and nonhuman primates. For the first time, these big data sets give us both a broad and exceptionally detailed picture of both biochemical activity along the genome and how DNA sequences have changed over time.”

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‘Designer Babies’ Debate Should Start, Scientists Say

BabiesRapid progress in genetics is making “designer babies” more likely and society needs to be prepared, leading scientists have told the BBC. Dr Tony Perry, a pioneer in cloning, has announced precise DNA editing at the moment of conception in mice. In the journal Scientific Reports, he details precisely editing the genome of mice at the point DNA from the sperm and egg come together. Dr Perry, who is based at the University of Bath, told the BBC: “We used a pair of molecular scissors and a molecular sat-nav that tells the scissors where to cut. It is approaching 100% efficiency already, it’s a case of ‘you shoot you score’.”

This has reopened questions about genetically modifying people. Prof Perry added: “On the human side, one has to be very cautious. There are heritable diseases coded by mutations in DNA and some people could say, ‘I don’t want my children to have these mutations.’” This includes conditions such as cystic fibrosis and genes that increase the risk of cancer. Prof Robin Lovell-Badge, from the UK Medical Research Council, has been influential in the debate around making babies from three people and uses the Crispr technology in his own lab. He said testing embryos for disease during IVF would be the best way of preventing diseases being passed down through the generations. It would also be useful in circumstances when all embryos would carry the undesirable, risky genes.

Prof Lovell-Badge told the BBC News website: “Obviously in the UK, this is not allowed and there would have to be a change in regulations, which I suspect would have enormous problems. But it is something that needs to start to be debated.”

Environment, not genes, plays starring role in human immune variation, study finds

A study of twins conducted by Stanford University School of Medicine investigators shows that our environment, more than our heredity, plays the starring role in determining the state of our immune system, the body’s primary defense against disease. This is especially true as we age, the study indicates.

Much has been made of the role genes play in human health. Stunning advances in gene-sequencing technologies, in concert with their plummeting costs, have turned many scientists’ attention to minute variations in the genome — the entire toolbox of genes carried in virtually every cell in the body — in the hope of predicting people’s future health. Such studies have revealed a genetic contribution to health outcomes. But, with some notable exceptions, very few individual genetic variants contribute much to particular health conditions. “The idea in some circles has been that if you sequence someone’s genome, you can tell what diseases they’re going have 50 years later,” said Mark Davis, PhD, professor of microbiology and director of Stanford’s Institute for Immunity, Transplantation and Infection. But while genomic variation clearly plays a key role in some diseases, he said, the immune system has to be tremendously adaptable in order to cope with unpredictable episodes of infection, injury and tumor formation. “The immune system has to think on its feet,” said Davis, senior author of the new study, which will be published Jan. 15 in Cell. Lead authorship is shared by former Stanford postdoctoral scholars Petter Brodin, MD, PhD, and Vladimir Jojic, PhD.

Examining differences in the levels and activity states of these components within pairs of monozygotic and dizygotic twins, the Stanford scientists found that in three-quarters of the measurements, nonheritable influences — such as previous microbial or toxic exposures, vaccinations, diet and dental hygiene — trumped heritable ones when it came to accounting for differences within a pair of twins. This environmental dominance was more pronounced in older identical twins (age 60 and up) than in younger twins (under age 20).

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2015 | Jessica Lynch Alfaro, et.al – Spatial and temporal patterns of diversification on the Amazon: A test of the riverine hypothesis for all diurnal primates of Rio Negro and Rio Branco in Brazil

ISG faculty, Dr. Jessica Lynch Alfaro, Dr. Michael E. Alfaro, et al, have published a paper titled “Spatial and temporal patterns of diversification on the Amazon: A test of the riverine hypothesis for all diurnal primates of Rio Negro and Rio Branco in Brazil” in Molecular Phylogenetics and Evolution.

Abstract:
The role of Amazonian rivers as drivers of speciation through vicariance remains controversial. Here we explore the riverine hypothesis by comparing spatial and temporal concordances in pattern of diversification for all diurnal primates of Rio Negro and its largest tributary, Rio Branco. We built a comprehensive comparative phylogenetic timetree to identify sister lineages of primates based on mitochondrial cytochrome b DNA sequences from 94 samples, including 19 of the 20 species of diurnal primates from our study region and 17 related taxa from elsewhere. Of the ten primate genera found in this region, three had populations on opposite banks of Rio Negro that formed reciprocally monophyletic clades, with roughly similar divergence times (Cebus: 1.85 Ma, HPD 95% 1.19–2.62; Callicebus: 0.83 Ma HPD 95% 0.36–1.32, Cacajao: 1.09 Ma, 95% HPD 0.58–1.77). This also coincided with time of divergence of several allopatric species of Amazonian birds separated by this river as reported by other authors. Our data offer support for the riverine hypothesis and for a Plio-Pleistocene time of origin for Amazonian drainage system. We showed that Rio Branco was an important geographical barrier, limiting the distribution of six primate genera: Cacajao, Callicebus, Cebus to the west and Pithecia, Saguinus, Sapajus to the east. The role of this river as a vicariant agent however, was less clear. For example, Chiropotes sagulata on the left bank of the Rio Branco formed a clade with C. chiropotes from the Amazonas Department of Venezuela, north of Rio Branco headwaters, with C. israelita on the right bank of the Rio Branco as the sister taxon to C. chiropotes + C. sagulata. Although we showed that the formation of the Rio Negro was important in driving diversification in some of our studied taxa, future studies including more extensive sampling of markers across the genome would help determine what processes contributed to the evolutionary history of the remaining primate genera.

2015 | Jessica Lynch Alfaro, et.al – Biogeography of the marmosets and tamarins (Callitrichidae)

ISG faculty, Dr. Jessica Lynch Alfaro, Dr. Michael E. Alfaro, et al, have published a paper titled “Biogeography of the marmosets and tamarins (Callitrichidae)” in Molecular Phylogenetics and Evolution.

Abstract:
The marmosets and tamarins, Family Callitrichidae, are Neotropical primates with over 60 species and subspecies that inhabit much of South America. Although callitrichids exhibit a remarkable widespread distribution, attempts to unravel their biogeographic history have been limited by taxonomic confusion and the lack of an appropriate statistical biogeographic framework. Here, we construct a time-calibrated multi-locus phylogeny from GenBank data and the callitrichid literature for 38 taxa. We use this framework to conduct statistical biogeographic analyses of callitrichids using BioGeoBEARS. The DIVAj model is the best supported reconstruction of biogeographic history among our analyses and suggests that the most recent common ancestor to the callitrichids was widespread across forested regions c. 14 Ma. There is also support for multiple colonizations of the Atlantic forest region from the Amazon basin, first by Leontopithecus c. 11 Ma and later by Callithrix c. 5 Ma. Our results show support for a 9 million year old split between a small-bodied group and large-bodied group of tamarins. These phylogenetic data, in concert with the consistent difference in body size between the two groups and geographical patterns (small-bodied tamarins and large-bodied tamarins have an unusually high degree of geographic overlap for congeners) lend support to our suggestion to split Saguinus into two genera, and we propose the use of distinct generic names; Leontocebus and Saguinus, respectively.

2015 | Jessica Lynch Alfaro, et.al – Biogeography of squirrel monkeys (genus Saimiri): South-central Amazon origin and rapid pan-Amazonian diversification of a lowland primate

ISG faculty, Dr. Jessica Lynch Alfaro, Dr. Michael E. Alfaro, et al, have published a paper titled “Biogeography of squirrel monkeys (genus Saimiri): South-central Amazon origin and rapid pan-Amazonian diversification of a lowland primate” in Molecular Phylogenetics and Evolution.

Abstract:

The squirrel monkey, Saimiri, is a pan-Amazonian Pleistocene radiation. We use statistical phylogeographic methods to create a mitochondrial DNA-based timetree for 118 squirrel monkey samples across 68 localities spanning all Amazonian centers of endemism, with the aim of better understanding (1) the effects of rivers as barriers to dispersal and distribution; (2) the area of origin for modern Saimiri; (3) whether ancestral Saimiriwas a lowland lake-affiliated or an upland forest taxa; and (4) the effects of Pleistocene climate fluctuation on speciation. We also use our topology to help resolve current controversies in Saimiri taxonomy and species relationships. The Rondônia and Inambari centers in the southern Amazon were recovered as the most likely areas of origin for Saimiri. The Amazon River proved a strong barrier to dispersal, and squirrel monkey expansion and diversification was rapid, with all speciation events estimated to occur between 1.4 and 0.6 Ma, predating the last three glacial maxima and eliminating climate extremes as the main driver of squirrel monkey speciation. Saimiri expansion was concentrated first in central and western Amazonia, which according to the “Young Amazon” hypothesis was just becoming available as floodplain habitat with the draining of the Amazon Lake. Squirrel monkeys also expanded and diversified east, both north and south of the Amazon, coincident with the formation of new rivers. This evolutionary history is most consistent with a Young Amazon Flooded Forest Taxa model, suggesting Saimiri has always maintained a lowland wetlands niche and was able to greatly expand its range with the transition from a lacustrine to a riverine system in Amazonia. Saimiri vanzolinii was recovered as the sister group to one clade of Saimiri ustus, discordant with the traditional Gothic vs. Roman morphological division of squirrel monkeys. We also found paraphyly within each of the currently recognized species: S. sciureusS. ustus, and S. macrodon. We discuss evidence for taxonomic revision within the genus Saimiri, and the need for future work using nuclear markers.