Genome‐wide DNA and phenotypic information supports recent colonization of South American grasslands by Correndera Pipit (Aves, Motacillidae)

2021 ◽  
Author(s):  
Heraldo V. Norambuena ◽  
Paul Els ◽  
Pedro F. Victoriano ◽  
Lacey Knowles
Keyword(s):  
South American ◽  
Phenotypic Information ◽  
Genome Wide

scholarly journals Genome-wide Association Study of Non-syndromic Orofacial Clefts in a Multiethnic Sample of Families and Controls Identifies Novel Regions

2020 ◽  
Author(s):  
Nandita Mukhopadhyay ◽  
Eleanor Feingold ◽  
Lina Moreno-Uribe ◽  
George Wehby ◽  
Luz Consuelo Valencia-Ramirez ◽  
...  
Keyword(s):  
Native American ◽  
Cleft Lip ◽  
Genome Wide Association Study ◽  
Population Level ◽  
Allele Frequencies ◽  
Genome Wide Association ◽  
South American ◽  
Orofacial Clefts ◽  
Public Health Burden ◽  
Genome Wide

AbstractOrofacial clefts (OFCs) are among the most prevalent craniofacial birth defects worldwide and create a significant public health burden. The majority of OFCs are non-syndromic and vary in prevalence by ethnicity. Africans have the lowest prevalence of OFCs (∼ 1/2,500), Asians have the highest prevalence (∼1/500), European and Latin Americans lie somewhere in the middle (∼1/800 and 1/900 respectively). Thus, ethnicity appears to be a major determinant of the risk of developing OFC. The Pittsburgh Orofacial Clefts Multiethnic study was designed to explore this ethnic variance, comprising a large number of families and individuals (∼12,000 individuals) from multiple populations worldwide: US and Europe, Asians, mixed Native American/Caucasians, and Africans. In this current study, we analyzed 2,915 OFC cases, 6,044 unaffected individuals related to the OFC cases, and 2,685 controls with no personal or family history of OFC. Participants were grouped by their ancestry into African, Asian, European, and Central and South American subsets, and genome-wide association run on the combined sample as well as the four ancestry-based groups. We observed 22 associations to cleft lip with or without cleft palate at 18 distinct loci with p-values < 1e-06, including 10 with genome-wide significance (< 5e-08), in the combined sample and within ancestry groups. Three loci - 2p12 (rs62164740, p=6.27e-07), 10q22.2 (rs150952246, p=3.14e-07), and 10q24.32 (rs118107597, p=8.21e-07) are novel. Nine were in or near known OFC loci - PAX7, IRF6, FAM49A, DCAF4L2, 8q24.21, NTN1, WNT3-WNT9B, TANC2, and RHPN2. The majority of the associations were observed only in the combined sample, European, and Central and South American groups. We investigated whether the observed differences in association strength were a) purely due to sample sizes, b) due to systematic allele frequency difference at the population level, or (c) due to the fact certain OFC-causing variants confer different amounts of risk depending on ancestral origin, by comparing effect sizes to observed allele frequencies of the effect allele in our ancestry-based groups. While some of the associations differ due to systematic differences in allele frequencies between groups, others show variation in effect size despite similar frequencies across ancestry groups.

scholarly journals Comparative Analysis of Chlamydia psittaci Genomes Reveals the Recent Emergence of a Pathogenic Lineage with a Broad Host Range

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Timothy D. Read ◽  
Sandeep J. Joseph ◽  
Xavier Didelot ◽  
Brooke Liang ◽  
Lisa Patel ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
New World ◽  
Evolutionary Dynamics ◽  
Chlamydia Psittaci ◽  
South American ◽  
Content Type ◽  
Sexually Transmitted ◽  
Genome Wide ◽  
Life Threatening ◽  
History Of

ABSTRACT Chlamydia psittaci is an obligate intracellular bacterium. Interest in Chlamydia stems from its high degree of virulence as an intestinal and pulmonary pathogen across a broad range of animals, including humans. C. psittaci human pulmonary infections, referred to as psittacosis, can be life-threatening, which is why the organism was developed as a bioweapon in the 20th century and is listed as a CDC biothreat agent. One remarkable recent result from comparative genomics is the finding of frequent homologous recombination across the genome of the sexually transmitted and trachoma pathogen Chlamydia trachomatis. We sought to determine if similar evolutionary dynamics occurred in C. psittaci. We analyzed 20 C. psittaci genomes from diverse strains representing the nine known serotypes of the organism as well as infections in a range of birds and mammals, including humans. Genome annotation revealed a core genome in all strains of 911 genes. Our analyses showed that C. psittaci has a history of frequently switching hosts and undergoing recombination more often than C. trachomatis. Evolutionary history reconstructions showed genome-wide homologous recombination and evidence of whole-plasmid exchange. Tracking the origins of recombinant segments revealed that some strains have imported DNA from as-yet-unsampled or -unsequenced C. psittaci lineages or other Chlamydiaceae species. Three ancestral populations of C. psittaci were predicted, explaining the current population structure. Molecular clock analysis found that certain strains are part of a clonal epidemic expansion likely introduced into North America by South American bird traders, suggesting that psittacosis is a recently emerged disease originating in New World parrots. IMPORTANCE Chlamydia psittaci is classified as a CDC biothreat agent based on its association with life-threatening lung disease, termed psittacosis, in humans. Because of the recent remarkable findings of frequent recombination across the genome of the human sexually transmitted and ocular trachoma pathogen Chlamydia trachomatis, we sought to determine if similar evolutionary dynamics occur in C. psittaci. Twenty C. psittaci genomes were analyzed from diverse strains that may play a pathogenic role in human disease. Evolution of the strains revealed genome-wide recombination occurring at a higher rate than for C. trachomatis. Certain strains were discovered to be part of a recent epidemic clonal expansion originating in South America. These strains may have been introduced into the United States from South American bird traders, suggesting that psittacosis is a recently emerged disease originating in New World parrots. Our analyses indicate that C. psittaci strains have a history of frequently switching hosts and undergoing recombination.

Admixture In Sickle Cell Disease Defined By Genome Wide Ancestry Informative Markers Varies By Geographic Region In The United States

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 995-995
Author(s):  
Zhengyuan Wang ◽  
Lena Diaw ◽  
Michael Dizon ◽  
Marci Barr ◽  
Meghan Quinn ◽  
...  
Keyword(s):  
Native American ◽  
North America ◽  
Sickle Cell ◽  
Genetic Admixture ◽  
South American ◽  
Genetic Modifiers ◽  
Ancestry Informative Markers ◽  
Genome Wide ◽  
The Us ◽  
Ancestry Proportions

Abstract Genome wide association studies (GWAS) are an important tool for identifying complex human disease loci. A key variable for GWAS is the degree of admixture or recent mixing of previously isolated populations. Undetected admixture can lead to spurious associations, although it may also be used as a strategy for mapping by admixture linkage disequilibrium (MALD). Development of reagents to identify admixture and to perform MALD may help to identify genetic modifiers of sickle cell disease (SCD). We have examined ancestry and genetic admixture in SCD patients living in North America. We first examined ancestry from family histories for 649 adults recruited to the Bethesda Sickle Cell Cohort Study in the eastern US, where 61% of subjects are African American, 22% African, 12% Caribbean or South American and 1.8% of other origins. We hypothesized that the high proportion of subjects from the Africa ancestry group would diminish the expected degree of admixture in the Bethesda cohort compared to other SCD cohorts. To assess admixture at the genetic level, we identified ancestry informative markers (AIMs) from 3,804,602 SNPs genotyped by HapMap Phase III in CEU (European) and YRI (Nigeria) populations. These SNPs were combined with a published admixture mapping panel, yielding a new MALD panel of 2251 AIMs. We assessed the performance of our AIM panel by genotyping 221 HapMap individuals and 489 adults from the Bethesda cohort with an overall completion rate of 98.51% using Illumina iSelect arrays. HapMap samples had 98% concordance with publicly available data. Out of 2251 candidate markers, only 1806 successfully passed all quality controls (289 SNPs could not be genotyped; 82 were not AIMs; 74 had low concordance with HapMap). Using our HapMap genotype data, this admixture panel has a mean δ (difference in allele frequencies between populations) of 0.712 (SD 0.118) with an average inter-marker distance of 1.862 Mb. The utility of this 1806 marker panel for genome wide MALD in SCD was demonstrated with a proof of concept scan to map the known genetic locus underlying SCD in the Bethesda cohort. To compare admixture in the Bethesda cohort to other SCD populations, we defined a subset of AIMs (n=360) that distinguish 6 major geo-ethnic groups from the Human Genome Diversity Panel (n=952 individuals). These results suggest that these 360 markers can distinguish contributions from geo-ethnic ancestry groups besides African and European populations. Using these markers in the Bethesda cohort, principle components analysis (PCA) showed African American or Caribbean/South American subjects had a wider range of admixture compared to Africans or HapMap populations (CEU, YRI and CHB). We then compared admixture proportions in the Bethesda cohort to 2 additional SCD populations, including 469 anonymous samples from a newborn screen SCD cohort in the western US and 439 SCD adults from a clinical trial in North America and Europe (WalkPhasst). Comparison of these SCD cohorts to 3 HapMap populations using PCA showed nearly 50% of the variation is explained by 2 major vectors that distinguish European/African and Asian/Native American ancestry. Finally, we compared admixture proportions across all 3 SCD cohorts using Structure. Here, we observed significant differences in ancestry proportions arising from Africa, Europe and Asia/Americas (P<0.001 by ANOVA). Specifically, African ancestry proportions were 0.640, 0.700, and 0.510 from the Bethesda cohort, WalkPhasst, and western newborns (all pairwise comparisons P<0.01), respectively. Significantly, there were differences between the cohorts from different regions of the US, where the Bethesda cohort had 0.039 Asian/Native American ancestry compared to 0.085 in the western SCD newborns (P<0.001). We conclude that there are significant admixture differences in SCD populations from eastern and western regions of the US. Overall, SCD patients in North America have a variable degree of genetic admixture that could affect interpretation of candidate gene or GWA studies. Furthermore, the degree of admixture adjustment varies for SCD subjects from different geographic regions within the US. Finally, our proof of concept studies suggest SCD may be ideal for MALD whole genome scans to identify genetic modifiers. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The genetic prehistory of the Andean highlands 7,000 Years BP though European contact

2018 ◽  
Author(s):  
John Lindo ◽  
Randall Haas ◽  
Courtney Hofman ◽  
Mario Apata ◽  
Mauricio Moraga ◽  
...  
Keyword(s):  
Pathogen Resistance ◽  
High Elevation ◽  
South American ◽  
European Contact ◽  
The Andes ◽  
Complex Modes ◽  
Genome Wide ◽  
Complex Process ◽  
Complex Picture ◽  
Andean Highlands

AbstractThe peopling of the Andean highlands above 2500m in elevation was a complex process that included cultural, biological and genetic adaptations. Here we present a time series of ancient whole genomes from the Andes of Peru, dating back to 7,000 calendar years before present (BP), and compare them to 64 new genome-wide genetic variation datasets from both high and lowland populations. We infer three significant features: a split between low and high elevation populations that occurred between 9200-8200 BP; a population collapse after European contact that is significantly more severe in South American lowlanders than in highland populations; and evidence for positive selection at genetic loci related to starch digestion and plausibly pathogen resistance after European contact. Importantly, we do not find selective sweep signals related to known components of the human hypoxia response, which may suggest more complex modes of genetic adaptation to high altitude.One Sentence SummaryAncient DNA from the Andes reveals a complex picture of human adaptation from early settlement to the colonial period.

scholarly journals The genomic landscape of Mexican Indigenous populations brings insights into the peopling of the Americas

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Humberto García-Ortiz ◽  
Francisco Barajas-Olmos ◽  
Cecilia Contreras-Cubas ◽  
Miguel Ángel Cid-Soto ◽  
Emilio J. Córdova ◽  
...  
Keyword(s):  
Demographic History ◽  
Indigenous Populations ◽  
South American ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Genomic Landscape ◽  
A Genome ◽  
Peopling Of The Americas ◽  
History Of ◽  
Genetic Makeup

AbstractThe genetic makeup of Indigenous populations inhabiting Mexico has been strongly influenced by geography and demographic history. Here, we perform a genome-wide analysis of 716 newly genotyped individuals from 60 of the 68 recognized ethnic groups in Mexico. We show that the genetic structure of these populations is strongly influenced by geography, and our demographic reconstructions suggest a decline in the population size of all tested populations in the last 15–30 generations. We find evidence that Aridoamerican and Mesoamerican populations diverged roughly 4–9.9 ka, around the time when sedentary farming started in Mesoamerica. Comparisons with ancient genomes indicate that the Upward Sun River 1 (USR1) individual is an outgroup to Mexican/South American Indigenous populations, whereas Anzick-1 was more closely related to Mesoamerican/South American populations than to those from Aridoamerica, showing an even more complex history of divergence than recognized so far.

scholarly journals Genetic variation for tolerance to the downy mildew pathogen Peronospora variabilis in genetic resources of quinoa (Chenopodium quinoa)

2020 ◽  
Author(s):  
Carla Colque-Little ◽  
Miguel Correa Abondano ◽  
Ole Søgard Lund ◽  
Daniel Buchvaldt Amby ◽  
Hans-Peter Piepho ◽  
...  
Keyword(s):  
Genetic Resources ◽  
Downy Mildew ◽  
Mixed Models ◽  
Genetic Basis ◽  
Chenopodium Quinoa ◽  
South American ◽  
Sources Of Resistance ◽  
Saponin Content ◽  
Genome Wide ◽  
Grain Crop

AbstractBackgroundQuinoa (Chenopodium quinoa Willd.) is an ancient grain crop that is tolerant to abiotic stress and has favorable nutritional properties. Downy mildew is the main disease of quinoa and is caused by infections of the biotrophic oomycete Peronospora variabilis Gaüm. Since the disease causes major yield losses, identifying sources of downy mildew tolerance in genetic resources and understanding its genetic basis are important goals in quinoa breeding.ResultsWe infected 132 South American genotypes, three Danish cultivars and the weedy relative C. album with a single isolate of P. variabilis under greenhouse conditions and observed a large variation in disease traits like severity of infection, which ranged from 5% to 83%. Linear mixed models revealed a significant effect of genotypes on disease traits with high heritabilities (0.72 to 0.81). Factors like altitude at site of origin or seed saponin content did not correlate with mildew tolerance, but stomatal width was weakly correlated with severity of infection. Despite the strong genotypic effects on mildew tolerance, genome-wide association mapping with 88 genotypes failed to identify significant marker-trait associations indicating a polygenic architecture of mildew tolerance.ConclusionsThe strong genetic effects on mildew tolerance allow to identify genetic resources, which are valuable sources of resistance in future quinoa breeding.

scholarly journals Genetic variation for tolerance to the downy mildew pathogen Peronospora variabilis in genetic resources of quinoa (Chenopodium quinoa)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Carla Colque-Little ◽  
Miguel Correa Abondano ◽  
Ole Søgaard Lund ◽  
Daniel Buchvaldt Amby ◽  
Hans-Peter Piepho ◽  
...  
Keyword(s):  
Genetic Resources ◽  
Downy Mildew ◽  
Mixed Models ◽  
Genetic Basis ◽  
Chenopodium Quinoa ◽  
South American ◽  
Sources Of Resistance ◽  
Saponin Content ◽  
Genome Wide ◽  
Grain Crop

Abstract Background Quinoa (Chenopodium quinoa Willd.) is an ancient grain crop that is tolerant to abiotic stress and has favorable nutritional properties. Downy mildew is the main disease of quinoa and is caused by infections of the biotrophic oomycete Peronospora variabilis Gaüm. Since the disease causes major yield losses, identifying sources of downy mildew tolerance in genetic resources and understanding its genetic basis are important goals in quinoa breeding. Results We infected 132 South American genotypes, three Danish cultivars and the weedy relative C. album with a single isolate of P. variabilis under greenhouse conditions and observed a large variation in disease traits like severity of infection, which ranged from 5 to 83%. Linear mixed models revealed a significant effect of genotypes on disease traits with high heritabilities (0.72 to 0.81). Factors like altitude at site of origin or seed saponin content did not correlate with mildew tolerance, but stomatal width was weakly correlated with severity of infection. Despite the strong genotypic effects on mildew tolerance, genome-wide association mapping with 88 genotypes failed to identify significant marker-trait associations indicating a polygenic architecture of mildew tolerance. Conclusions The strong genetic effects on mildew tolerance allow to identify genetic resources, which are valuable sources of resistance in future quinoa breeding.

scholarly journals Phylogeny, transposable element and sex chromosome evolution of the basal lineage of birds

2019 ◽  
Author(s):  
Zongji Wang ◽  
Jilin Zhang ◽  
Xiaoman Xu ◽  
Christopher Witt ◽  
Yuan Deng ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Sequence Divergence ◽  
South American ◽  
Sex Chromosome Evolution ◽  
Rapid Speciation ◽  
Genome Wide ◽  
Divergence Pattern ◽  
Female Specific

AbstractSex chromosomes of mammals and most birds are heteromorphic, while those of many paleognaths (ratites and tinamous) are inexplicably homomorphic. To dissect the mechanisms underlying the different tempo of sex chromosome evolution, we produced high-quality genomes of 12 paleognathous species, and reconstructed their phylogeny based on alignments of the non-coding sequences extending to nearly 40% of the genome. Our phylogenomic tree grouped the South American rheas and tinamous together, and supported the independent evolution of gigantism and loss of flight among ratites. The small-bodied tinamous have much higher rates of genome-wide substitutions and transposon turnovers. Yet majorities of both have retained exceptionally long recombining regions occupying over half of the entire sex chromosome, with the rest sex-linked regions diverging from each other at a much lower rate relative to neognathous birds. Each species exhibits a punctuated sequence divergence pattern between sex chromosomes termed ‘evolutionary strata’, because of stepwise suppression of recombination. We concluded that all paleognaths share one evolutionary stratum with all other birds, and convergently formed between one to three strata after their rapid speciation. Contrary to the classic notion, we provided clear evidence that the youngest stratum of some tinamous formed without chromosomal inversion. Intriguingly, some of the encompassing W-linked genes have upregulated their expression levels in ovary, probably due to the female-specific selection. We proposed here that the unique male-only parental care system of paleognaths has reduced the intensity of sexual selection, and contributed to these species’ low rates of sex chromosome evolution. We also provided novel insights into the evolution of W-linked genes at their early stages.

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