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Since the first Spanish settlers brought horses to America centuries ago, several local varieties and breeds have been established in the New World. These were generally a consequence of the admixture of the different breeds arriving from Europe. In some instances, local horses have been selectively bred for specific traits, such as appearance, endurance, strength, and gait. We looked at the genetics of two breeds, the Puerto Rican Non-Purebred (PRNPB) (also known as the “Criollo”) horses and the Puerto Rican Paso Fino (PRPF), from the Caribbean Island of Puerto Rico. While it is reasonable to assume that there was a historic connection between the two, the genetic link between them has never been established. In our study, we started by looking at the genetic ancestry and diversity of current Puerto Rican horse populations using a 668 bp fragment of the mitochondrial DNA D-loop (HVR1) in 200 horses from 27 locations on the island. We then genotyped all 200 horses in our sample for the “gait-keeper” DMRT3 mutant allele previously associated with the paso gait especially cherished in this island breed. We also genotyped a subset of 24 samples with the Illumina Neogen Equine Community genome-wide array (65,000 SNPs). This data was further combined with the publicly available PRPF genomes from other studies. Our analysis show an undeniable genetic connection between the two varieties in Puerto Rico, consistent with the hypothesis that PRNPB horses represent the descendants of the original genetic pool, a mix of horses imported from the Iberian Peninsula and elsewhere in Europe. Some of the original founders of PRNRB population must have carried the “gait-keeper” DMRT3 allele upon arrival to the island. From this admixture, the desired traits were selected by the local people over the span of centuries. We propose that the frequency of the mutant “gait-keeper” allele originally increased in the local horses due to the selection for the smooth ride and other characters, long before the PRPF breed was established. To support this hypothesis, we demonstrate that PRNPB horses, and not the purebred PRPF, carry a signature of selection in the genomic region containing the DMRT3 locus to this day. The lack of the detectable signature of selection associated with the DMRT3 in the PRPF would be expected if this native breed was originally derived from the genetic pool of PRNPB horses established earlier and most of the founders already had the mutant allele. Consequently, selection specific to PRPF later focused on allels in other genes (including CHRM5, CYP2E1, MYH7, SRSF1, PAM, PRN and others) that have not been previously associated with the prized paso gait phenotype in Puerto Rico or anywhere else.

Contemporary genetic variation among Latin Americans human groups reflects population migrations shaped by complex historical, social and economic factors. Consequently, admixture patterns may vary by geographic regions ranging from countries to neighborhoods. We examined the geographic variation of admixture across the island of Puerto Rico and the degree to which it could be explained by historic and social events. We analyzed a census-based sample of 642 Puerto Rican individuals that were genotyped for 93 ancestry informative markers (AIMs) to estimate African, European and Native American ancestry. Socioeconomic status (SES) data and geographic location were obtained for each individual. There was significant geographic variation of ancestry across the island. In particular, African ancestry demonstrated a decreasing East to West gradient that was partially explained by historical factors linked to the colonial sugar plantation system. SES also demonstrated a parallel decreasing cline from East to West. However, at a local level, SES and African ancestry were negatively correlated. European ancestry was strongly negatively correlated with African ancestry and therefore showed patterns complementary to African ancestry. By contrast, Native American ancestry showed little variation across the island and across individuals and appears to have played little social role historically. The observed geographic distributions of SES and genetic variation relate to historical social events and mating patterns, and have substantial implications for the design of studies in the recently admixed Puerto Rican population. More generally, our results demonstrate the importance of incorporating social and geographic data with genetics when studying contemporary admixed populations.

The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, we investigate the population genetic history of this region by characterizing patterns of genome-wide variation among 330 individuals from three of the Greater Antilles (Cuba, Puerto Rico, Hispaniola), two mainland (Honduras, Colombia), and three Native South American (Yukpa, Bari, and Warao) populations. We combine these data with a unique database of genomic variation in over 3,000 individuals from diverse European, African, and Native American populations. We use local ancestry inference and tract length distributions to test different demographic scenarios for the pre- and post-colonial history of the region. We develop a novel ancestry-specific PCA (ASPCA) method to reconstruct the sub-continental origin of Native American, European, and African haplotypes from admixed genomes. We find that the most likely source of the indigenous ancestry in Caribbean islanders is a Native South American component shared among inland Amazonian tribes, Central America, and the Yucatan peninsula, suggesting extensive gene flow across the Caribbean in pre-Columbian times. We find evidence of two pulses of African migration. The first pulse--which today is reflected by shorter, older ancestry tracts--consists of a genetic component more similar to coastal West African regions involved in early stages of the trans-Atlantic slave trade. The second pulse--reflected by longer, younger tracts--is more similar to present-day West-Central African populations, supporting historical records of later transatlantic deportation. Surprisingly, we also identify a Latino-specific European component that has significantly diverged from its parental Iberian source populations, presumably as a result of small European founder population size. We demonstrate that the ancestral components in admixed genomes can be traced back to distinct sub-continental source populations with far greater resolution than previously thought, even when limited pre-Columbian Caribbean haplotypes have survived.

Genomics is an increasingly important part of biology research. However, educating undergraduates in genomics is not yet a standard part of life sciences curricula. We believe this is, in part, due to a lack of standard concepts for the teaching of genomics. To address this deficit, the members of the Genomics Education Alliance created a set of genomics concepts that was then further refined by input from a community of undergraduate educators who engage in genomics instruction. The final genomics concepts list was compared to existing learning frameworks, including the Vision and Change initiative (V&C), as well as ones for genetics, biochemistry and molecular biology, and bioinformatics. Our results demonstrate that the new genomics framework fills a niche not addressed by previous inventories. This new framework should be useful to educators seeking to design stand-alone courses in genomics as well as those seeking to incorporate genomics into existing coursework. Future work will involve designing curriculum and assessments to go along with this genomics learning framework.

Advances in both morphological and molecular techniques have uncovered many lineages across the tree of life, and Neotropical vertebrates are no exception. Sphaerodactylus geckos (Sphaerodactylidae) are abundant and important components of the Neotropical herpetofauna, but few studies have thoroughly investigated them using a combination of morphology and modern molecular genetic methods. Here, we combine morphological and genetic data to describe a new species of Sphaerodactylus from the northwestern karst region of Puerto Rico. The new species is compared to other closely related and sympatric species of Sphaerodactylus. Morphological analysis shows that the combination of small body size (median SVL = 21.5 mm), lepidosis, skull morphology, and coloration of the head differentiates the new species from its closest relatives, including the related species, Sphaerodactylus klauberi. Comparing sequences of the mitochondrial 16S rRNA gene showed a genetic distance between S. klauberi and the new species of 5.1–5.6%, which is similar to genetic distances among other recognized gecko species. This is the first new species of Sphaerodactylus to be described from Puerto Rico in nearly a century, highlighting the continued need to evaluate and chronicle biological diversity even in well-studied regions. Las filogenias moleculares han elucidado múltiples linajes en el árbol de la vida, incluyendo varios vertebrados neotropicales. Las salamanquitas del género Sphaerodactylus (Sphaerodactylidae) son abundantes y forman una parte importante de la herpetofauna neotropical. Este género ha sido investigado recientemente utilizando métodos moleculares modernos. En este artículo se describe una nueva especie del género Sphaerodactylus, procedente de la región kárstica del noroeste de Puerto Rico. Los individuos de la nueva especie fueron comparados con especies afines y simpátricas. El análisis morfológico muestra que la combinación entre el tamaño corporal, escamación, morfología del cráneo y coloración cefálica, distinguen a la especie nueva de otras especies cercanas filogenéticamente, incluyendo su especie hermana Sphaerodactylus klauberi. Al comparar secuencias del gen mitocondrial 16S rRNA se observó una distancia genética de 5.1–5.6% entre la especie nueva y S. klauberi, dicha distancia es similar a la que existe entre otras especies descritas de salamaquitas. Ha pasado casi un siglo desde que la última especie de Sphaerodactylus de Puerto Rico fue descrita, ésto resalta la necesidad de seguir evaluando y catalogando la biodiversidad, inclusive en áreas que han sido investigadas a profundidad.

Islands have been used as model systems for studies of speciation and extinction since Darwin published his observations about finches found on the Galapagos. Amazon parrots inhabiting the Greater Antillean Islands represent a fascinating model of species diversification. Unfortunately, many of these birds are threatened as a result of human activity and some, like the Puerto Rican parrot, are now critically endangered. In this study we used a combination of de novo and reference-assisted assembly methods, integrating it with information obtained from related genomes to perform genome reconstruction of three amazon species. First, we used whole genome sequencing data to generate a new de novo genome assembly for the Puerto Rican parrot (Amazona vittata). We then improved the obtained assembly using transcriptome data from Amazona ventralis and used the resulting sequences as a reference to assemble the genomes Hispaniolan (A. ventralis) and Cuban (Amazona leucocephala) parrots. Finally, we, annotated genes and repetitive elements, estimated genome sizes and current levels of heterozygosity, built models of demographic history and provided interpretation of our findings in the context of parrot evolution in the Caribbean.

Risk genes for Mendelian (single-gene) disorders (SGDs) are consistent across populations, but pathogenic risk variants that cause SGDs are typically population-private. The goal was to develop “QChip1,” an inexpensive genotyping microarray to comprehensively screen newborns, couples, and patients for SGD risk variants in Qatar, a small nation on the Arabian Peninsula with a high degree of consanguinity. Over 108 variants in 8445 Qatari were identified for inclusion in a genotyping array containing 165,695 probes for 83,542 known and potentially pathogenic variants in 3438 SGDs. QChip1 had a concordance with whole-genome sequencing of 99.1%. Testing of QChip1 with 2707 Qatari genomes identified 32,674 risk variants, an average of 134 pathogenic alleles per Qatari genome. The most common pathogenic variants were those causing homocystinuria (1.12% risk allele frequency), and Stargardt disease (2.07%). The majority (85%) of Qatari SGD pathogenic variants were not present in Western populations such as European American, South Asian American, and African American in New York City and European and Afro-Caribbean in Puerto Rico; and only 50% were observed in a broad collection of data across the Greater Middle East including Kuwait, Iran, and United Arab Emirates. This study demonstrates the feasibility of developing accurate screening tools to identify SGD risk variants in understudied populations, and the need for ancestry-specific SGD screening tools.

Little is known about the natural history of the Sphaerodactylus species endemic to the three islands located in the Mona Passage separating the Greater Antillean islands of Hispaniola and Puerto Rico. In this study, parts of two mitochondrial genes, 16S rRNA and 12S rRNA, were sequenced to determine the relationships between the sphaerodactylids that live in the Mona Passage and other Caribbean species from the same genus. While the main goal was to identify the biogeographical origin of these species, we also identified a genetically distinct type of dwarf gecko that warrants future evaluation as a possible new species. According to the reconstructed phylogenies, we propose a stepwise model of colonization wherein S. nicholsi from southwestern Puerto Rico or a very close ancestor gave rise through a founder event to Sphaerodactylus monensis on Mona Island. In a similar fashion, S. monensis or a very close ancestor on Mona Island gave rise to S. levinsi on Desecheo Island. This study also suggests that the most recent common ancestor between the species from the islands in the Mona Passage and Puerto Rico existed approximately 3 MYA. Parts of two mitochondrial genes were sequenced from several Sphaerodactylus species collected from Puerto Rico, Hispaniola, and two small islands located between the formers. A stepwise model of colonization is proposed, wherein S. nicholsi from southwestern Puerto Rico or a very close ancestor gave rise through a founder event to Sphaerodactylus monensis on Mona Island and, in a similar fashion, S. monensis or a very close ancestor on Mona Island gave rise to S. levinsi on Desecheo Island.

Amazon parrots (Amazona spp.) colonized the islands of the Greater Antilles from the Central American mainland, but there has not been a consensus as to how and when this happened. Today, most of the five remaining island species are listed as endangered, threatened, or vulnerable as a consequence of human activity. We sequenced and annotated full mitochondrial genomes of all the extant Amazon parrot species from the Greater Antillean (A. leucocephala (Cuba), A. agilis, A. collaria (both from Jamaica), A. ventralis (Hispaniola), and A. vittata (Puerto Rico)), A. albifrons from mainland Central America, and A. rhodocorytha from the Atlantic Forest in Brazil. The assembled and annotated mitogenome maps provide information on sequence organization, variation, population diversity, and evolutionary history for the Caribbean species including the critically endangered A. vittata. Despite the larger number of available samples from the Puerto Rican Parrot Recovery Program, the sequence diversity of the A. vittata population in Puerto Rico was the lowest among all parrot species analyzed. Our data support the stepping-stone dispersal and speciation hypothesis that has started approximately 3.47 MYA when the ancestral population arrived from mainland Central America and led to diversification across the Greater Antilles, ultimately reaching the island of Puerto Rico 0.67 MYA. The results are presented and discussed in light of the geological history of the Caribbean and in the context of recent parrot evolution, island biogeography, and conservation. This analysis contributes to understating evolutionary history and empowers subsequent assessments of sequence variation and helps design future conservation efforts in the Caribbean.

The aim of this chapter is to offer an interpretation of the seemingly contradictory results of the combined information of the 2000 U.S. Census data for Puerto Rico and the results of the 2003 University of Puerto Rico, Mayagüez Campus, Racial Classification Study (UPRM Study). On the 2000 U.S. Census, 80.5 percent of Puerto Ricans classified themselves as White, while 15.4 percent considered themselves either Black, African American, American Indian, Alaska Native, Asian, or some other race. Three years later, as part of the UPRM Study, only 45.9 percent chose to classify themselves as White, while 30.6 percent declined the