Mate selection: A useful approach to maximize genetic gain and control inbreeding in genomic and conventional oil palm (Elaeis guineensis Jacq.) hybrid breeding.

Genomic selection (GS) is an effective method for the genetic improvement of complex traits in plants and animals. Optimization approaches could be used in conjunction with GS to further increase its efficiency and to limit inbreeding, which can increase faster with GS. Mate selection (MS) typically uses a metaheuristic optimization algorithm, simulated annealing, to optimize the selection of individuals and their matings. However, in species with long breeding cycles, this cannot be studied empirically. Here, we investigated this aspect with forward genetic simulations on a high-performance computing cluster and massively parallel computing, considering the oil palm hybrid breeding example. We compared MS and simple methods of inbreeding management (limitation of the number of individuals selected per family, prohibition of self-fertilization and combination of these two methods), in terms of parental inbreeding and genetic progress over four generations of genomic selection and phenotypic selection. The results showed that, compared to the conventional method without optimization, MS could lead to significant decreases in inbreeding and increases in annual genetic progress, with the magnitude of the effect depending on MS parameters and breeding scenarios. The optimal solution retained by MS differed by five breeding characteristics from the conventional solution: selected individuals covering a broader range of genetic values, fewer individuals selected per full-sib family, decreased percentage of selfings, selfings preferentially made on the best individuals and unbalanced number of crosses among selected individuals, with the better an individual, the higher the number of times he is mated. Stronger slowing-down in inbreeding could be achieved with other methods but they were associated with a decreased genetic progress. We recommend that breeders use MS, with preliminary analyses to identify the proper parameters to reach the goals of the breeding program in terms of inbreeding and genetic gain.

Incidencia de enfermedad cerebrovascular en un servicio de Medicina Interna / Incidence of cerebrovascular disease in an Internal Medicine service

Resumen: ANTECEDENTES La enfermedad vascular cerebral constituye un importante motivo de ingreso al área de medicina interna y según los diferentes grupos de edad, sexo y manejo hospitalario, alcanza altos niveles de letalidad; en 2010 ocupó el sexto lugar entre las principales causas de defunción en México. OBJETIVO Conocer la estadística de los padecimientos isquémicos y hemorrágicos en el servicio de Medicina Interna con base en datos recopilados con archivos clínicos del Hospital General de Matamoros, Tamaulipas. MATERIAL Y MÉTODO Estudio observacional, retrospectivo y transversal en el que mediante el uso del expediente clínico se obtuvo la información de las variables de edad, género, fecha de ingreso, fecha de egreso, pruebas diagnósticas, tomografías realizadas durante el ingreso del paciente al Hospital General de Matamoros, Tamaulipas, del 26 de junio de 2012 al 21 de junio de 2017. RESULTADOS De 4619 pacientes ingresados al Hospital de Matamoros, Tamaulipas, 438 pacientes tuvieron diagnóstico de enfermedad vascular cerebral (9.4%); de ellos, el hemorrágico representó 18.5%, el isquémico 46.3% y 33.8% no tuvo diagnóstico. La edad media fue de 65 años, con intervalo de 22 a 99 años. Los días de estancia tuvieron variancia de 16.2 días, con media de 2 días, mínimo de 0 y máximo de 26 días. CONCLUSIONES El estudio muestra al hombre con mayor tendencia, con más afectación en personas más jóvenes, lo que difiere del resto de las investigaciones de México y Latinoamérica.

Abstract: BACKGROUND Cerebrovascular disease (CVD) is an important reason for admission to the area of internal medicine in hospitals and with some variations depending on the different age groups, gender, and hospital management. It causes high levels of lethality, occupying in 2010 the sixth place within the main causes of death in Mexico. OBJECTIVE To know the statistics of ischemic and hemorrhagic diseases in the internal medicine service based on data collected from clinical files at the Hospital of Matamoros, Tamaulipas, Mexico. MATERIAL AND METHOD An observational, retrospective and transversal study was done from clinical records to obtain data about the variables of age, gender, date of admission, date of discharge, and diagnostic tests and tomographies performed during the patient's stay at the Hospital of Matamoros, Tamaulipas, Mexico, from June 26th 2012 to June 21st 2017. RESULTS We found that 4619 patients were admitted at the Hospital of Matamoros, Tamaulipas, Mexico. From this group, 438 patients were diagnosed with cerebrovascular disease (9.4%), the hemorrhagic accounted for 18.5%, the ischemic 46.3% and 33.8% were not diagnosed. The age variable had a mean of 65 years old (22-99 years). The days of stay variable had a mean of 2.0 days, a variance of 16.2 days (interval: 0-26 days). CONCLUSIONS The study showed that cerebrovascular disease is present more in men than in women and that cerebrovascular disease affects more frequently to younger people. These findings have an important variation compared to similar research findings in Mexico and Latin America.

Long-term genomic selection for heterosis without dominance in multiplicative traits: case study of bunch production in oil palm.

BACKGROUND: To study the potential of genomic selection for heterosis resulting from multiplicative interactions between additive and antagonistic components, we focused on oil palm, where bunch production is the product of bunch weight and bunch number. We simulated two realistic breeding populations and compared current reciprocal recurrent selection (RRS) with reciprocal recurrent genomic selection (RRGS) over four generations. All breeding strategies aimed at selecting the best individuals in parental populations to increase bunch production in hybrids. For RRGS, we obtained the parental genomic estimated breeding values using GBLUP with hybrid phenotypes as data records and population specific allele models. We studied the effects of four RRGS parameters on selection response and genetic parameters: (1) the molecular data used to calibrate the GS model: in RRGS_PAR, we used parental genotypes and in RRGS_HYB we also used hybrid genotypes; (2) frequency of progeny tests (model calibration); (3) number of candidates and (4) number of genotyped hybrids in RRGS_HYB. RESULTS: We concluded that RRGS could increase the annual selection response compared to RRS by decreasing the generation interval and by increasing the selection intensity. With 1700 genotyped hybrids, calibration every four generations and 300 candidates per generation and population, selection response of RRGS_HYB was 71.8 % higher than RRS. RRGS_PAR with calibration every two generations and 300 candidates was a relevant alternative, as a good compromise between the annual response, risk around the expected response, increased inbreeding and cost. RRGS required inbreeding management because of a higher annual increase in inbreeding than RRS. CONCLUSIONS: RRGS appeared as a valuable method to achieve a long-term increase in the performance for a trait showing heterosis due to the multiplicative interaction between additive and negatively correlated components, such as oil palm bunch production.

Genomic selection prediction accuracy in a perennial crop: case study of oil palm (Elaeis guineensis Jacq.).

KEY MESSAGE: Genomic selection empirically appeared valuable for reciprocal recurrent selection in oil palm as it could account for family effects and Mendelian sampling terms, despite small populations and low marker density. Genomic selection (GS) can increase the genetic gain in plants. In perennial crops, this is expected mainly through shortened breeding cycles and increased selection intensity, which requires sufficient GS accuracy in selection candidates, despite often small training populations. Our objective was to obtain the first empirical estimate of GS accuracy in oil palm (Elaeis guineensis), the major world oil crop. We used two parental populations involved in conventional reciprocal recurrent selection (Deli and Group B) with 131 individuals each, genotyped with 265 SSR. We estimated within-population GS accuracies when predicting breeding values of non-progeny-tested individuals for eight yield traits. We used three methods to sample training sets and five statistical methods to estimate genomic breeding values. The results showed that GS could account for family effects and Mendelian sampling terms in Group B but only for family effects in Deli. Presumably, this difference between populations originated from their contrasting breeding history. The GS accuracy ranged from -0.41 to 0.94 and was positively correlated with the relationship between training and test sets. Training sets optimized with the so-called CDmean criterion gave the highest accuracies, ranging from 0.49 (pulp to fruit ratio in Group B) to 0.94 (fruit weight in Group B). The statistical methods did not affect the accuracy. Finally, Group B could be preselected for progeny tests by applying GS to key yield traits, therefore increasing the selection intensity. Our results should be valuable for breeding programs with small populations, long breeding cycles, or reduced effective size.

Estimation of genealogical coancestry in plant species using a pedigree reconstruction algorithm and application to an oil palm breeding population.

KEY MESSAGE: Explicit pedigree reconstruction by simulated annealing gave reliable estimates of genealogical coancestry in plant species, especially when selfing rate was lower than 0.6, using a realistic number of markers. Genealogical coancestry information is crucial in plant breeding to estimate genetic parameters and breeding values. The approach of Fernández and Toro (Mol Ecol 15:1657-1667, 2006) to estimate genealogical coancestries from molecular data through pedigree reconstruction was limited to species with separate sexes. In this study it was extended to plants, allowing hermaphroditism and monoecy, with possible selfing. Moreover, some improvements were made to take previous knowledge on the population demographic history into account. The new method was validated using simulated and real datasets. Simulations showed that accuracy of estimates was high with 30 microsatellites, with the best results obtained for selfing rates below 0.6. In these conditions, the root mean square error (RMSE) between the true and estimated genealogical coancestry was small (<0.07), although the number of ancestors was overestimated and the selfing rate could be biased. Simulations also showed that linkage disequilibrium between markers and departure from the Hardy-Weinberg equilibrium in the founder population did not affect the efficiency of the method. Real oil palm data confirmed the simulation results, with a high correlation between the true and estimated genealogical coancestry (>0.9) and a low RMSE (<0.08) using 38 markers. The method was applied to the Deli oil palm population for which pedigree data were scarce. The estimated genealogical coancestries were highly correlated (>0.9) with the molecular coancestries using 100 markers. Reconstructed pedigrees were used to estimate effective population sizes. In conclusion, this method gave reliable genealogical coancestry estimates. The strategy was implemented in the software MOLCOANC 3.0.

Estudio de un factor de riesgo coronario, el colesterol, en un sector de un área de salud / Study of a coronary risk factor, cholesterol, in a health area

Con la ayuda de las organizaciones de masa se realizó un muestreo al azar, en 100 casos de pacientes con más de 40 años de edad buscando los hipercolesterolémicos. A 23 casos con cifras altas de colesterol en sangre, se les evaluaron otros factores de riesgo coronario (presencia de diabetes, hipertensión, obesidad, etcétera). El 70 de los pacientes hipercolesterolémicos presentó riesgo coronario de importancia y el 75 electrocardiogramas con lesiones sugestivas o establecidas de cardiopatías isquémica. Se insiste en aplicar medidas de prevención primaria en el área de salud para prevenir las cardiopatías isquémicas