Author Archives: DWN

Mouse NRF2 loss recapitulates heritable impacts of paternal cigarette smoke exposure in next-generation offspring

As these GEITP pages have often stated, any trait (phenotype) reflects contributions of: genetics (differences in DNA sequence); epigenetic factors (chromosomal events independent of DNA sequence: DNA methylation, RNA interference, histone modifications, and chromatin remodeling); environmental effects (smoking, diet, lifestyle); … Continue reading

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Origin and the elaboration of a major evolutionary transition in individuality

This topic fits nicely the theme of gene-environment interactions — the “environmental signal” is the life cycle of Camponotini (ant tribe containing two extinct genera and eight extant genera — including the carpenter ant); the “response to the signal” is … Continue reading

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Spontaneous generation of prions and transmissible PrP amyloid in a humanized transgenic mouse model of A117V Gerstmann-Sträussler-Scheinker (GSS)

“Consensus science” is the risky situation whereby “a majority of ‘scientists’ might agree upon a ‘fact’ they fervently believe to be true.” The consensus may or may not turn out to be confirmed by further research, but we should remember … Continue reading

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Combined Utility of Many Disease and Risk Factor Polygenic Risk Scores (PRS) for Stratifying Risk of All-Cause Mortality; and of Colorectal Cancer

This topic involves heavy population genetics and genomics, so bear with me. Genome-wide association studies (GWAS) first began in ~2005, and the number of GWAS has exploded ever since. Fundamentally, researchers choose a phenotype (trait) and then sequence the genomes … Continue reading

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Interesting New COVID-19 Theory Emerging from Supercomputer Analysis: the Bradykinin Hypothesis

Interesting New COVID-19 Theory Emerging from Supercomputer Analysis A closer look at the Bradykinin hypothesis Thomas Smith Aug 31· 2020 3d rendering of multiple coronavirus. Earlier this summer, the Summit supercomputer at Oak Ridge National Lab in Tennessee set about … Continue reading

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These GEITP pages often cover topics of evolution, including the Great Human Diaspora (i.e. the multiple Homo sapiens migrations out of Africa, between 25,000 and more than 100,000 years ago; these migrations resulted in the five major geographically-isolated subgroups — Africans, East Asians, Oceanians, Europeans and Amerindians). A longstanding controversy about Oceanian history concerns the possibility of prehistoric admixture (i.e. hanky-panky) between Polynesian and Amerindian populations. The early peopling of Polynesia attracted worldwide interest in 1947, when the Norwegian explorer Thor Heyerdahl set sail on the Kon-Tiki expedition to test his migration theory; the crew left Peru on a wooden raft and — after 101 days and a voyage of more than 7,000 kilometers — they reached Polynesian shores, thus proving the possibility of early travel from South America westward to these Pacific islands. Heyerdahl challenged the scientific community’s view that evidence pointed instead to populating Polynesia by people traveling east from Asia; his idea that Polynesia was initially populated by South Americans was generally criticized by scholars. However, the sweet potato (a South American plant) has a long history of cultivation in eastern Polynesia. Previous scientists — investigating this question through genetics — had focused on Easter Island (Rapa Nui). As the Polynesian island closest to the Americas, and the one having the most elaborate megalithic culture (giant heads made of stone), Rapa Nui has been considered a likely locus for contact. High-resolution analyses of human leukocyte antigen (HLA) alleles had revealed an Amerindian component in modern individuals with self-identified Rapanui ancestry. However, in the only two whole-genome sequencing (WGS) studies of Rapanui variation — only one of eight modern individuals, and one of five skeletal remains — was Amerindian DNA found. Thus, these studies reached opposing conclusions about pre-European contact between Polynesian individuals on Rapa Nui and Amerindian individuals. To date, no WGS studies have considered the possibility of pre-European Amerindian contact on other Polynesian islands. Authors [see attached article & editorial] first analyzed 807 individuals from 17 island populations, and 15 Pacific coast Amerindian groups, searching for signs of admixture. Authors then performed high-density WGS analyses of a smaller data set (166 Rapanui and 188 additional individuals from islands spanning the eastern Pacific). They found conclusive evidence for prehistoric contact of Polynesian individuals with Amerindian individuals (~1200 AD) simultaneously with individuals in remote Oceania. This study therefore strongly suggests that a single contact event occurred in eastern Polynesia — before the settlement of Rapa Nui — between Polynesian individuals and an Amerindian group most closely related to the indigenous inhabitants of present-day Colombia. In other words, Thor Heyerdahl’s theory was correct…!! 😊 DwN Nature 23 Jul 2020; 583: 572-577 & Editorial pp 524-525

This paper (in press, Journal of Medical Virology) — provides a very succinct accurate analysis of the structure of the SARS-CoV-2 virus’ mRNA-encoded gene products. Without going overboard with political accusations, authors give several types of evidence for the likelihood … Continue reading

Posted in Center for Environmental Genetics | Comments Off on These GEITP pages often cover topics of evolution, including the Great Human Diaspora (i.e. the multiple Homo sapiens migrations out of Africa, between 25,000 and more than 100,000 years ago; these migrations resulted in the five major geographically-isolated subgroups — Africans, East Asians, Oceanians, Europeans and Amerindians). A longstanding controversy about Oceanian history concerns the possibility of prehistoric admixture (i.e. hanky-panky) between Polynesian and Amerindian populations. The early peopling of Polynesia attracted worldwide interest in 1947, when the Norwegian explorer Thor Heyerdahl set sail on the Kon-Tiki expedition to test his migration theory; the crew left Peru on a wooden raft and — after 101 days and a voyage of more than 7,000 kilometers — they reached Polynesian shores, thus proving the possibility of early travel from South America westward to these Pacific islands. Heyerdahl challenged the scientific community’s view that evidence pointed instead to populating Polynesia by people traveling east from Asia; his idea that Polynesia was initially populated by South Americans was generally criticized by scholars. However, the sweet potato (a South American plant) has a long history of cultivation in eastern Polynesia. Previous scientists — investigating this question through genetics — had focused on Easter Island (Rapa Nui). As the Polynesian island closest to the Americas, and the one having the most elaborate megalithic culture (giant heads made of stone), Rapa Nui has been considered a likely locus for contact. High-resolution analyses of human leukocyte antigen (HLA) alleles had revealed an Amerindian component in modern individuals with self-identified Rapanui ancestry. However, in the only two whole-genome sequencing (WGS) studies of Rapanui variation — only one of eight modern individuals, and one of five skeletal remains — was Amerindian DNA found. Thus, these studies reached opposing conclusions about pre-European contact between Polynesian individuals on Rapa Nui and Amerindian individuals. To date, no WGS studies have considered the possibility of pre-European Amerindian contact on other Polynesian islands. Authors [see attached article & editorial] first analyzed 807 individuals from 17 island populations, and 15 Pacific coast Amerindian groups, searching for signs of admixture. Authors then performed high-density WGS analyses of a smaller data set (166 Rapanui and 188 additional individuals from islands spanning the eastern Pacific). They found conclusive evidence for prehistoric contact of Polynesian individuals with Amerindian individuals (~1200 AD) simultaneously with individuals in remote Oceania. This study therefore strongly suggests that a single contact event occurred in eastern Polynesia — before the settlement of Rapa Nui — between Polynesian individuals and an Amerindian group most closely related to the indigenous inhabitants of present-day Colombia. In other words, Thor Heyerdahl’s theory was correct…!! 😊 DwN Nature 23 Jul 2020; 583: 572-577 & Editorial pp 524-525

Kon Tiki — revisited: South American genes found in Polynesia

These GEITP pages often cover topics of evolution, including the Great Human Diaspora (i.e. the multiple Homo sapiens migrations out of Africa, between 25,000 and more than 100,000 years ago; these migrations resulted in the five major geographically-isolated subgroups — … Continue reading

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Impact of Environmental Chemicals on the Gut Microbiome

As these GEITP pages continue to emphasize, a trait (phenotype; e.g. height, weight, green eyes, blood pressure, a disease such as schizophrenia or obesity, adverse response to a drug) reflects the contribution of: genetics (DNA sequence differences in genes), epigenetic … Continue reading

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An Estimate of Climate Sensitivity

An Estimate of Climate Sensitivity Charles Rotter / August 31, 2020 Reposted from edmhdotme Assuming the logarithmic diminution premise to be appropriate, this diagram indicates: there is no direct, straight-line relationship between atmospheric CO2 concentration and its influence on temperature … Continue reading

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Genetics Steps In — to Help Tell the Story of Human Origins

This very recent article (Sept 2020) from The Scientist was offered to me to share on these GEITP pages. Written in semi-layman terms, the history of Homo sapiens evolution is detailed — which gives some continuity to the various articles … Continue reading

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