Potential Donor Populations Research Articles

Uniparental and biparental markers unravel invasion pathways, population admixture, and genetic structure in naturalized rainbow trout (Oncorhynchus mykiss).

The present study combined uniparental mtDNA and biparental SNPs to illuminate the invasion and colonization pathways of rainbow trout, Oncorhynchus mykiss, one of the world's most widespread invasive fishes, that has been intensively propagated in Chile, South America. The specific aims of the study were (i) to evaluate potential donor populations, which could be either from the species' native range in North America or from introduced populations in Europe, by comparing mtDNA D-loop/control region haplotypes; and (ii) to assess the factors that have shaped genetic diversity and contemporary genetic structure of rainbow trout populations introduced to Chile through SNP genotyping. The authors comprehensively sampled 24 sites in 12 basins ranging from the High Andean Plateau (Altiplano, 18° S) to northern Patagonia (41° S). Results of the mtDNA data of naturalized trout populations from rivers in the Altiplano (northern Chile) differed from those collected in central and southern Chile, suggesting an origin from North American hatcheries. Naturalized trout populations in central and southern Chile, on the contrary, shared haplotypes with specimens found in European hatcheries. The southern and central Chile populations also contained rare haplotypes, possibly indicating potential spread through aquaculture escapes. Results of the SNP analysis revealed higher allelic richness for trout sampled in sites influenced by commercial aquaculture than sites without commercial aquaculture, likely due to increased admixture between aquaculture broodstock and naturalized trout. The analysis further uncovered some complex patterns of divergent trout populations with low genetic diversity as well as increased relatedness between individuals from isolated sites, suggesting possible local populations. A comprehensive characterization of genetic diversity and structure of rainbow trout should help identify management areas that may augment socioeconomic benefits while preventing the spread and further impacts on biodiversity.

Lower SARS-CoV-2 Seroprevalence among Cancer Patients in Sub-Saharan Africa.

Background: Despite the high COVID-19 morbidity and mortality rates across the world, the reported rates in sub-Saharan Africa (SSA), which has a higher burden of other infectious diseases and overwhelmed healthcare systems, remain relatively low. This study aims to better understand the potential factors that contribute to this phenomenon, especially among cancer patients who are considered as a high-risk group for developing severe COVID-19. Methods: Plasma samples collected during the COVID-19 pandemic from SARS-CoV-2 unvaccinated cancer and potential blood donor populations were analyzed for SARS-CoV-2 (spike and nucleocapsid proteins) antibodies by an immunofluorescence assay. The relationships between SARS-CoV-2 seroprevalences and study variables were determined using a logistic regression analysis. Results: High seroprevalence against the SARS-CoV-2 spike and nucleocapsid proteins were found among the SARS-CoV-2 unvaccinated COVID-19 pandemic populations in SSA. However, the cancer patients demonstrated a lower seroprevalence compared to potential blood donors. There was also an association between mild COVID-19 symptoms with prior tuberculosis vaccination among cancer patients. Conclusion: Cancer patients in SSA tend to have a relatively lower SARS-CoV-2 seroprevalence compared to potential blood donors recruited from the same geographic locations during the COVID-19 pandemic. More study is required to determine its cause and potential impact on SARS-CoV-2 vaccination among cancer patients.

Contrasting genetic trajectories of endangered and expanding red fox populations in the western U.S

As anthropogenic disturbances continue to drive habitat loss and range contractions, the maintenance of evolutionary processes will increasingly require targeting measures to the population level, even for common and widespread species. Doing so requires detailed knowledge of population genetic structure, both to identify populations of conservation need and value, as well as to evaluate suitability of potential donor populations. We conducted a range-wide analysis of the genetic structure of red foxes in the contiguous western U.S., including a federally endangered distinct population segment of the Sierra Nevada subspecies, with the objectives of contextualizing field observations of relative scarcity in the Pacific mountains and increasing abundance in the cold desert basins of the Intermountain West. Using 31 autosomal microsatellites, along with mitochondrial and Y-chromosome markers, we found that populations of the Pacific mountains were isolated from one another and genetically depauperate (e.g., estimated Ne range = 3–9). In contrast, red foxes in the Intermountain regions showed relatively high connectivity and genetic diversity. Although most Intermountain red foxes carried indigenous western matrilines (78%) and patrilines (85%), the presence of nonindigenous haplotypes at lower elevations indicated admixture with fur-farm foxes and possibly expanding midcontinent populations as well. Our findings suggest that some Pacific mountain populations could likely benefit from increased connectivity (i.e., genetic rescue) but that nonnative admixture makes expanding populations in the Intermountain basins a non-ideal source. However, our results also suggest contact between Pacific mountain and Intermountain basin populations is likely to increase regardless, warranting consideration of risks and benefits of proactive measures to mitigate against unwanted effects of Intermountain gene flow.

Assessment of National Organ Donation Rates and Organ Procurement Organization Metrics

Organ transplant is a life-saving procedure for patients with end-stage organ failure. In the US, organ procurement organizations (OPOs) are responsible for the evaluation and procurement of organs from donors who have died; however, there is controversy regarding what measures should be used to evaluate their performance. To evaluate OPO performance metrics using combined mortality and donation data and quantify the associations of population demographics with donation metrics. This national cohort study includes data from the US organ transplantation system from January 2008 through December 2017. All individuals who died within the US, as reported by the National Death index, were included. Death, organ donation, and donation eligibility. Evaluation of the variation in donation metrics and the use of ineligible donors by OPO and demographic subgroup. This study included 17 501 742 deaths and 75 769 deceased organ donors (45 040 men [59.4%]; 51 908 White individuals [68.5%]). Of these donors, 15 857 (20.9%) were not eligible, as defined by the OPOs. The median donation metrics by OPO were 0.004 (range, 0.002-0.012) donors per death, 0.89 (range, 0.68-1.30) donors per eligible death, and 0.72 (range, 0.57-0.86) eligible donors per eligible death. The OPOs in the upper quartile of the overall eligible donors per eligible death metric were in the upper quartile of annual rankings on 90 of 140 occasions (64.3%). There was little overlap in top-performing OPOs between metrics; an OPO in the upper quartile for 1 metric was also in the upper quartile for the other metrics on 37 of 570 occasions (6.5% of the time). The median donor eligibility rate, defined as the number of eligible donors per donor, was 0.79 (range, 0.61-0.95) across OPOs. Age (eg, 65 to 84 years, coefficient, -0.55 [SE, 0.03]; P < .001; vs those aged 18 to 34 years), sex (male individuals, -0.09 [SE, 0.02]; P < .001; vs female individuals), race (eg, Black individuals, 0.35 [SE, 0.02]; P < .001; vs White individuals), cause of death (eg, central nervous system tumor, 0.48 [SE, 0.08]; P < .001; vs anoxia), year (eg, 2016-2017: -0.10 [SE, 0.03]; P < .001; vs 2008-2009), and OPO were associated with the use of ineligible donors; OPO was a significant factor associated with performance in all metrics (χ256, 500.5; P < .001; coefficient range across individual OPOs, -0.15 [SE, 0.09] to 0.75 [SE, 0.09]), even after accounting for population differences. Female and non-White individuals were significantly less likely to be used as ineligible donors. We demonstrate significant variability in OPO performance rankings, depending on which donation metric is used. There were significant differences in OPO performance, even after accounting for differences in potential donor populations. Our data suggest significant variation in use of ineligible donors among OPOs, a source for increased donors. The performance of OPOs should be evaluated using a range of donation metrics.

An assessment of the seascape genetic structure and hydrodynamic connectivity for subtropical seagrass restoration

Seagrass ecosystems have suffered significant declines globally and focus is shifting to restoration efforts. A key component to successful restoration is an understanding of the genetic factors potentially influencing restoration success. This includes understanding levels of connectivity between restoration locations and neighboring seagrass populations that promote natural recovery (source and sink populations), the identification of potential donor populations, and assessment of genetic diversity of restored meadows and material used for restoration. In this study, we carry out genetic surveys of 352 individuals from 13 populations using 11 polymorphic microsatellite loci to inform seagrass restoration activities by: (1) understanding levels of genetic and genotypic diversity within meadows; and (2) understanding genetic structure and patterns of connectivity among these meadows to determine which source sites may be most appropriate to assist recovery of three restoration sites. The study identified high genotypic diversity within the locations analyzed from the Port of Gladstone and Rodd's Bay region, indicating sexual reproduction is important in maintaining populations. Overall, we detected significant genetic structuring among sites with the Bayesian structure analysis identifying genetic clusters that largely conformed to a northern, central, and southern region. This suggests limited gene flow between regions, although there does appear to be some connectivity within regions. The hydrodynamic models showed that seeds were largely locally retained, while fragments were more widely dispersed. Limited gene flow between regions suggests donor material for restoration should be sourced locally where possible.

Impact of Ex Vivo Lung Perfusion on Utilization of Potential Lung Donors in the United States

Ex vivo lung perfusion (EVLP) is a contemporary tool which aims to improve the utilization of marginal donor lungs. Little is known about the impact of EVLP on the utilization of potential donor organs on a national scale in the United States. This study examines whether EVLP is associated with increased lung utilization among potential donors in a contemporary cohort of United States patients. We used the Organ Procurement and Transplantation Network database to identify all adult potential deceased organ donors, including donors after brain death (DBD) and donors after circulatory determination of death (DCD) in the modern era of EVLP (2015-2018). Our main covariate of interest was use of EVLP, defined by perfusion of either or both lungs prior to transplantation. The primary study endpoint was lung utilization, defined as successful single or double lung transplantation of a potential organ donor. Our analysis was performed using a multivariable logistic regression model adjusted for donor demographics, clinical characteristics, and risk factors. We evaluated the association between EVLP and lung utilization separately among the DCD and DBD potential donor populations. We identified 11,857 potential donors of whom 1,608 (14%) were DCDs. EVLP use increased from 2% to 4% annually during the study period. Among DBD potential donors, EVLP was used in 2% (n=22). Lung utilization was 62% (n=6188) in grafts recovered without EVLP and 49% (n=108) with EVLP. Recovery with EVLP was associated with significantly lower lung utilization (adjusted OR 0.6, 95% CI 0.4-0.8) among DBD potential donors. Among DCD potential donors, EVLP was used in 6% (n=100). Lung utilization was 15% (n=234) without EVLP and 49% (n=49) with EVLP. Recovery with EVLP was associated with significantly improved lung utilization among DCD potential donors (adjusted OR 2.8, 95% CI 1.7-4.6). EVLP is associated with significantly higher lung utilization among potential DCD donors in the United States. In DBD donors, use of EVLP was likely a surrogate for unmeasured high-risk features and appeared to represent attempted salvage of organs that would otherwise have been discarded. EVLP can be a valuable tool to improve lung utilization among DCD donors and if employed more widely, may increase the pool of organs available for transplantation.

Modeling dispersal and spatial connectivity of macro-invertebrates in Danish waters: An agent-based approach

Marine organisms with planktonic life stages are subjected to extensive transport that results from the interactions between ocean currents and their behavioral responses to environmental changes in the course of their life. Questions remain on the identification of key drivers of dispersal and connectivity in marine populations as they can have multiple uses in the conservation and management of marine ecosystems. Here we investigate whether the open Kattegat, at the entrance to Baltic Sea, is the main source of recruitment to the benthos in associated estuaries and coastal sites through export of planktonic invertebrate larvae. We couple a 3D hydrodynamic ocean model (MIKE3FM) to an agent-based model and simulate the dispersal of macro-invertebrate populations in Danish waters. We use characteristic dispersal traits of the larval community (pelagic larval duration, spawning season, and settling behavior) and simulate dispersal processes within the muddy bottom habitats to derive recruitment rates and potential donor populations leading to population connectivity patterns on each site, one bay and two Danish fjords. We then use our recruitment results in the bay to compare them with field data on species diversity in the same area. A total of 48 different combinations of pelagic larval durations and spawning seasons of macro-invertebrates are simulated in two years 2004 and 2010. From these results, we conclude that the central and southern parts of the Danish waters are identified as important spawning grounds whereas the Kattegat does not seem to be the main provider of larvae into the selected sites. The model also predicts higher abundance and recruitment rates of macro-invertebrate larvae in 2010 compared to 2004. These results are supported by comparable species distribution data collected in the study area. Our results show the importance of an integrated modeling tool combining ocean circulation and biological traits to obtain a detailed description of dispersal and connectivity of macro-invertebrate community in the area, which can provide a more accurate baseline to manage marine biodiversity.

Integrating genetics and morphometrics in species conservation—A case study on the stone crayfish, Austropotamobius torrentium

The stone crayfish, Austropotamobius torrentium, is a freshwater crayfish species native to Central and Southeast Europe. Due to various, mostly anthropogenic factors the species is facing a dramatic decline in many European countries. In order to plan and implement protection measures, it is essential to collect extensive data on the species, including biological aspects and the major threats. Therefore, in the frame of a species conservation program in western Austria, we assessed the genetic relationship of the local endangered stone crayfish populations to populations in eastern Switzerland and southern Germany as well as their genetic diversity using mitochondrial and nuclear DNA markers. Population differentiation was measured applying both genetic and morphometric tools in order to estimate the suitability of potential donor populations for future restocking and reintroduction measures. The results showed a high degree of genetic homogeneity at the lineage level in the alpine stretch of the Rhine valley. Despite a rather low genetic diversity, nuclear markers provided signs of genetic divergence among populations even at a local scale. Due to the inconsistencies found between genetic and morphometric differentiation patterns, we highlight the importance of integrating both tools for the identification of suitable crayfish stocking material.

Polyphyletic ancestry of expanding Patagonian Chinook salmon populations

Chinook salmon native to North America are spreading through South America’s Patagonia and have become the most widespread anadromous salmon invasion ever documented. To better understand the colonization history and role that genetic diversity might have played in the founding and radiation of these new populations, we characterized ancestry and genetic diversity across latitude (39–48°S). Samples from four distant basins in Chile were genotyped for 13 microsatellite loci, and allocated, through probabilistic mixture models, to 148 potential donor populations in North America representing 46 distinct genetic lineages. Patagonian Chinook salmon clearly had a diverse and heterogeneous ancestry. Lineages from the Lower Columbia River were introduced for salmon open-ocean ranching in the late 1970s and 1980s, and were prevalent south of 43°S. In the north, however, a diverse assembly of lineages was found, associated with net-pen aquaculture during the 1990s. Finally, we showed that possible lineage admixture in the introduced range can confound allocations inferred from mixture models, a caveat previously overlooked in studies of this kind. While we documented high genetic and lineage diversity in expanding Patagonian populations, the degree to which diversity drives adaptive potential remains unclear. Our new understanding of diversity across latitude will guide future research.

Analysis of Reasons for Prospective Blood Donor Deferrals at Eric Williams Medical Sciences Complex Blood Collection Centre, in Trinidad and Tobago

Introduction: Blood banks must ensure reliability of blood supplies. However many prospective donors are temporarily deferred due to reasons that are preventable. Objective: To describe the reasons for deferral of prospective blood donors at a local Blood Collection Centre. Materials and Methods: This was a descriptive analysis of reasons for deferral of 488 prospective blood donors between April 2011 and May 2012. They were screened using the Pan American Health Organization 2009 guidelines. Haemoglobin was assessed using the Copper sulphate (CuSO4) Method: 293 subjects (60.04%), or HemoCue Hb201+: 195 subjects (39.96%). Results: 179(36.7%) were females aged 18 to 59years. The commonest reason for deferral was high blood pressure: 126donors (25.8%). Others included lack of sleep 27 (5.5%), not eating prior: 5(1.02%), drank alcohol/ smoked prior, 9 (1.84%), tattoo/piercing, 14 (2.87%), breast feeding, inter-current illnesses, and too soon after a previous donation. 57(11.7%), were deferred due to low haemoglobin. 16 (28.1%), were screened using CuSO4 and 41(71.9%) using HemoCue. Conclusion: A high percentage of deferrals were due to hypertension or reasons that would not potentially endanger the blood recipients and could be prevented. This emphasizes the need for education of potential donor populations in order to avoid unfruitful blood bank visits. Deferrals based on low haemoglobin were higher using Hemocue method.

From altruism to monetisation: Australian women's ideas about money, ethics and research eggs

We report the results of a qualitative study carried out in metropolitan Australia between 2009 and 2011 that canvassed the issue of payment for research oöcyte donation with participants drawn from three potential donor groups; fertility patients, reproductive donors and young, non-patient women. Research oöcytes are controversial tissues because women around the world have proved largely unwilling to donate them altruistically. In the ensuing international debate about procurement, the issue of money and its appropriate and inappropriate uses in tissue donation has taken centre stage. While there is now an abundance of expert commentary on this matter, there are almost no studies that probe this issue with potential donor populations. Our study asked the three groups of women about their understandings of altruistic, reimbursed, subsidised, compensated and paid donation for both reproductive and research eggs. We identify a resistance to the introduction of money into the sphere of reproductive donation, which the majority of respondents felt should remain an area of personalised gift relations. In the area of research donation we find a strong relationship between degrees of liquidity (the extent to which money is constrained or unconstrained) and a sense of ethical appropriateness. We also describe a culturally specific sense of fairness and equity among participants, associated with the relatively high public subsidisation of fertility treatment in Australia, which they used to benchmark their sense of appropriate and inappropriate uses of money. While the participant responses reflect the regulatory environment in Australia, particularly the absence of a US style market in reproductive oöcytes, they also make an important contribution to the global debate.

Genetic assessment of Atlantic salmon Salmo salar and sea trout Salmo trutta stocking in a Baltic Sea river

Microsatellite DNA variation was used to assess the outcome of stocking Atlantic salmon Salmo salar and migratory trout Salmo trutta in River Sävarå, N Sweden. No information on pre‐stocking genetic composition of S. salar and S. trutta in River Sävarå was available. In 2 year‐classes of S. salar smolt, microsatellite data indicated that post‐stocking genetic composition differed markedly (FST= 0·048) from the main donor strain, Byskeälven S. salar, and from other Gulf of Bothnia S. salar stocks (FST 0·047 and 0·132). The STRUCTURE programme failed to detect any substructuring within Sävarå salmon. It was concluded that only minor introgression estimated to a proportion of 0·11 (95% CI 0·07–0·16) has occurred in S. salar. Salmo trutta showed overall low differentiation among populations with maximum FST of 0·03 making analysis more cumbersome than in S. salar. Still, the SävaråS. trutta deviated significantly from potential donor populations, and STRUCTURE software supported that majority of trout in Sävarå formed a distinct genetic population. Admixture was more extensive in S. trutta and estimated to 0·17 (95% CI 0·10–0·25).

Using genetics to inform re-introduction strategies for the Chequered Skipper butterfly (Carterocephalus palaemon, Pallas) in England

The Chequered Skipper butterfly (Carterocephalus palaemon) is extinct in England but extant in Scotland and Continental Europe. The possibility of re-introducing the species is under active consideration by conservation bodies, but ecological differences between Scottish and English populations raise the question of which populations should donate individuals, Continental European, or Scottish? We used mitochondrial DNA sequences (CO I, CO II and Cyt b) from potential donor populations to test the hypothesis that ecological differences could have arisen as a result of differing routes of post-glacial colonisation from separate refugia and subsequent isolation of UK populations. Shared haplotypes between populations in Belgium, Norway, Scotland and England provides no evidence to support the hypothesis that populations in Scotland result from an alternative post-glacial colonisation route. As the genetic evidence remains equivocal we suggest that choice of donor stock for a re-introduction to England should be made primarily on ecological grounds.

REDUCED GENETIC DIVERSITY IN EELGRASS TRANSPLANTATIONS AFFECTS BOTH POPULATION GROWTH AND INDIVIDUAL FITNESS

The transplantation of eelgrass (Zostera marina) for mitigation results in reduced genetic diversity among individuals and populations- in southern California, the Chesapeake Bay, and New Hampshire. Although genetic variation determines the potential for eelgrass to adapt to the rapidly changing environment in its coastal and estuarine habitats, genetic considerations are not currently included in mitigation and restoration policy. I investigated where and how genetic diversity is lost during eelgrass transplantation. I then explored associations between genetic diversity and both vegetative propagation and sexual reproduction to evaluate the importance of genetic diversity for short-term population growth. Eelgrass beds used as donor populations vary in genetic diversity, and some have little or no detectable genetic diversity. Genetic diversity is reduced upon transplantation because donor plants are collected from small areas, leading to random sampling errors in selecting stock. This loss can be minimized by using information from regional surveys of genetic diversity and structure in potential donor populations and by revising donor stock collection. There were significant positive associations between genetic diversity and the sexual reproduction of eelgrass, with a similar trend for vegetative propagation. Individuals het- erozygous for glucose-phosphate isomerase (GPI) developed flowering shoots more than did homozygotes. More seeds germinated from a genetically diverse, untransplanted pop- ulation than from a transplanted population with low genetic diversity. A field transplan- tation of known multilocus genotypes revealed that leaf shoot density in high-diversity eelgrass increased almost twice as fast as in low-diversity eelgrass over 22 mo. In a me- socosm experiment under heat stress, eelgrass heterozygous for either GPI or malate de- hydrogenase (MDH) produced almost twice as many leaf shoots as homozygotes. The difference between treatments in all experiments increased over time. Together, these results imply that there could be economic incentives to planting genetically diverse eelgrass, and that genetic diversity contributes to eelgrass population viability even over the short term.

Identifying open-pollinated populations of field corn as sources of cold tolerance for improving sweet corn

Sweet corn has poor cold tolerance and adaptation to the European Atlantic coast. Our objectives were to identify sources of favorable alleles for improving cold tolerance of three sweet corn hybrids, to compare sources of cold tolerance and early vigor, and to provide additional information on the relationships among different classes of loci and estimators of favorable alleles for cold tolerance. Each of ten field corn populations was crossed to four sweet corn inbreds. The field by sweet corn hybrids, the populations, the inbreds and the target hybrids were evaluated under cold conditions. Estimates of the mean frequencies of four classes of loci in the populations, and six estimators of favorable alleles (lplμ', PTC, UBND, NI, PNGg, and PNGceg) and GCA were computed. The population by inbred crosses were significantly different for emergence proportion and survival. Correlations between lplμ', UBND, PTC and NI were high for emergence proportion. Most estimates of favorable alleles were significantly different from zero but not among populations. PTC was used to choose the best potential donor populations. The US Corn Belt Dent population AS-3(HT)C3 and the Spanish flint population Oroso were the best potential donors of favorable alleles for emergence proportion and survival under cold conditions, respectively. The ability to germinate and survive under cold conditions may be necessary, but it does not ensure adaptation to cold humid springs.

Methods to evaluate populations for alleles to improve an elite hybrid

Elite hybrids can be improved by the introgression of favorable alleles not already present in the hybrid. Our first objective was to evaluate several estimators derived from quantitative genetic theory that attempt to quantify the relative number of useful alleles in potential donor populations. Secondly, we wanted to evaluate two proposed ways of determining relatedness of donor populations to the parents of the elite hybrid. Two experiments, each consisting of 21 maize populations of known pedigree, were grown at three and four environments in Minnesota in 1991. Yield and plant height means were used to provide estimates of each of the following statistics: (1) LPLU, a minimally biased statistic, (2) UBND, the minimum estimate of an upper bound, (3) NI, the net improvement, (4) PTC, the predicted three-way cross, and (5) TCSC, the testcross of the populations. These statistics are biased estimators of the relative number of unique favorable alleles contained within a population compared to a reference elite hybrid. Based on rank correlations, all statistics except NI ranked populations similarly. The percent novel germplasm relative to the single cross to be improved was positively correlated with the estimates of favorable alleles except when NI was used as the estimator. The relationship estimators agreed with the genetic constitution of the donor populations. Strong positive correlations existed between diversity, based on the relationship rankings, and all the estimator rankings, except NI. Potential donor populations were effectively identified by LPLU, UBND, PTC, and TCSC. NI was not a good estimator of unique favorable alleles.