Population history of indigenous peoples of the Americas and Columbian Exchange Cultural areas of North America at time of European contact The European colonization of the Americas fundamentally changed the lives and cultures of the native peoples of the continents. The majority of these losses are attributed to the introduction of Afro-Eurasian diseases into the Americas.
Find articles by David P. Kirk Find articles by Kirsty A. Burdon Find articles by Kathryn P. Craig Find articles by Jamie E. Revised article and approved for publication: Received Jan 19; Accepted Jun Copyright Dimasi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
This article has been cited by other articles in PMC. Associated Data Table S1: Studies included in meta-analysis of human CCT measurements. Evidence from a range of studies indicates that central corneal thickness CCT is strongly genetically determined.
Support for a genetic component comes from data showing significant variation in CCT between different human ethnic groups. Interestingly, these studies also appear to show that skin pigmentation may influence CCT.
To validate these observations, we undertook the first analysis of CCT in an oculocutaneous albinism OCA and Ugandan cohort, populations with distinct skin pigmentation phenotypes.
Specific mutations within the melanin synthesis pathway were then investigated in mice for an association with CCT. These findings provide support for our hypothesis that pigmentation is associated with CCT and identifies pigment-related genes as candidates for developmental determination of a non-pigmented structure.
Introduction The cornea is a transparent, avascular tissue that covers the anterior surface of the eye. The cornea plays a fundamental role in refracting light into the eye, as well as acting as a protective barrier against the extra-ocular environment and pathogens.
Interest in central corneal thickness CCT has become widespread in the recent literature as its association with several ocular and non-ocular conditions becomes recognized. Most notably, CCT has been identified as a risk factor for the potentially blinding disease open-angle glaucoma  — but abnormal measurements have also been shown to manifest in anirida Ehlers-Danlos syndrome  — Marfan syndrome  and osteogenesis imperfecta .
In order to further understand the clinical relevance of this trait, the mechanisms underlying normal CCT variation need to be elucidated. As there is scant evidence of any environmental factors influencing CCT, it is probable that genetic factors play an important role in the determination of this trait.
Indeed, evidence from both twin and familial studies indicate that CCT is highly heritable  —  and recent studies have identified several genes associated with normal variation in CCT  — . Further evidence of the genetic nature of CCT comes from numerous studies which have found that CCT varies between different ethnic populations.
Whilst comparing the results of different studies is difficult, several present similar findings.
Caucasians for example, have been consistently associated with a thicker CCT than both their African and Australian Aboriginal counterparts.
In the absence of any confirmed environmental factors, this data implies that population specific genetic variants could be responsible for the variation in CCT. Given the striking differences in skin pigmentation between these groups, it also follows that dark skin is associated with a lower CCT.
To further investigate the relationship between human skin pigmentation and CCT, we assessed CCT in two human populations that had never previously been investigated for this trait, a group of individuals with oculocutaneous albinism OCA and a cohort from Uganda. In addition, a meta-analysis of all published human CCT data was undertaken, which included the Ugandan and Caucasian cohorts assessed in this study.
The purpose of the meta-analysis was to systematically investigate whether any association between CCT and skin pigmentation can be observed following examination of the literature. In order to validate the observations seen in human studies, we then examined CCT in 13 different inbred mouse strains.
The pigmentation status of the mouse coat colours was varied, with seven albino, two black, two dilute brown and two agouti strains. This permitted a direct examination of whether the pigmentation phenotype is correlated with CCT.
The potential association between skin pigmentation and a transparent tissue such as the cornea is an extremely novel finding and could potentially lead to the identification of genes involved in new developmental pathways.Aug 10, · The Forward enters its second hundred years at an intersection of history that has placed many strains on ethnic survival in America.
But even intermarriage and the disappearance of an immigrant. Across all strains there was a broad range of measurements, with a µm difference in mean CCT between the thinnest (DBA/1J) and thickest (AKR) strains. There was a significant difference between the CCT measurements across all strains (p.
Six Ethnic Communities in Central Queens, NY, Executive Summary Author(s): Robert C. Davis PERCEPTIONS OF THE POLICE AMONG MEMBERS OF SIX ETHNIC COMMUNITIES IN CENTRAL QUEENS, NY Relations between the police and ethnic minorities have experienced strains throughout U.S.
history. Police officers, who are most often White, and minority. That Falling Down was filmed in L.A. amid the riots is both ironic and telling: D-Fens’ entire narrative is driven by his misconception that he is the true victim, even as he marauds through the.
Latin America would match its 15th-century population early in the 19th century; it numbered 17 million in , 30 million in , 61 million in , million in , million in , million in , and million in Dec 14, · White America is dying off.
on its cover blending the nation’s predominant ethnic strains, a forecast of the effects of intermingling of genes.
the honorable word “liberal,” have no.