Estimates Of Genetic Diversity Research Articles

Stability Analysis and Genetic Variability in Buckwheat (Fagopyrum esculentum Moench.)

Aims: To estimate the genetic variability and to identify the stable buckwheat genotype for growth and yield parameters. Study Design: Eberhart and Russell model. Place and Duration of Study: Department of Plantation, Spices, Medicinal and Aromatic Crops, College of Horticulture, Bagalkot, Karnataka during Jan-April 2021-2022. Methodology: Fifteen genotypes of buckwheat were assessed for stability parameters for 15 characters across three environments i.e, full dose of recommended fertilizer (RDF), 3/4th dose of RDF and 1/2nd dose of RDF. The pooled data of these environments were used for estimation of genetic variability. Results: The heritability estimates were moderate to high for all the characters. The genetic advance over mean was found highest for number of clusters per cyme (35.05%), seed yield per plot (32.68%) and seed yield per hectare (32.72%). The genotype EC-104035 was found stable for seed yield per plant, per plot and hectare, EC-386667, EC-3222, Nilgiri local, PRB-1 and Sangla B-460 for thousand seed weight, IC-313134 and EC-3222 for plant height at 45 days after sowing and at harvest, Shimla B-1 for plant height at 15 days after sowing, IC-49671, IC-274429 and Sangla B-460 for number of branches at 30 DAS, PRB-1 for days to first flowering and Nilgiri local for days to 50 percent flowering. Conclusion: The genotypes stable for more traits with high genetic variability, will be considered for future breeding program.

Estimation of Breeding values and genetic variances at first exon-regionofIGF1 gene and its association of growth traits in Awassi sheep which are breeding in Iraq

Estimation of Breeding values and genetic variances at first exon-regionofIGF1 gene and its association of growth traits in Awassi sheep which are breeding in Iraq

Genetic diversity, heritability, and estimated breeding values for growth of domesticated Asian seabass Latescalcarifer from Thailand

To establish a new breeding program, genetic diversity of five domesticated populations and two commercial stocks of Asian seabass (Lates calcarifer) were examined. Moderate levels of genetic diversity based on microsatellite polymorphism were found. The number of alleles per locus (NA) was 3.429–11.571. Observed (Ho) and expected (He) heterozygosities were 0.416–0.772 and 0.423–0.805. FST and genetic heterogeneity analysis revealed significant genetic differences of most pairwise comparisons (P < 0.001). Genetic distance between populations was 0.000–0.703. Phylogenetic analysis divided examined populations to two genetic stocks; A: DOF-Chachoengsao 2, DOF-Songkhla, and DOF-Trang and B: Commercial Farm 1 (Phuket) and Commercial Farm 2 (Chachengsao), DOF-Chachoengsao 1 and DOF-Krabi. The base population (G0, 51 families) was established from crosses between these founder populations. Heritability and estimated breeding values (EBVs) for growth in G0 families were evaluated at 519 day post hatch (dph, mean body weight = 616.64 ± 266.80 g, N = 1655). The heritability (h2) for growth of L. calcarifer in this study was 0.386 ± 0.020. The additive genetic coefficient of variation was 28% indicating high potential of genetic improvement for growth in this population. The distribution of EBVs showed high variation both between and within families. Fish exhibiting high EBVs (SATREPS-DOF-G0-hEBVs) clustered with a phylogenetic clade A while the SATREPS-DOF-G0-lEBVs group was phylogenetically allocated to clade B. Genetic selection with +1SD criteria is expected to achieve genetic gain of 28.5% per generation. The information on genetic diversity and EBVs estimates allows efficient implementation of our ongoing breeding program of L. calcarifer.

Estimation of genetic diversity utilizing gene-targeted SCoT markers and morpho-chemotypic analyses in Senna alexandrina Mill. (Senna)

Senna, an industrial crop that generates foreign exchange, is planted predominantly in southern India. Senna leaves and pods grown in India are valued in international trade and the global market because they contain a high concentration of the chemical component sennosides. The current investigation was conducted in the CSIR-CIMAP experimental farm in Hyderabad, India. The experiment was designed in an RCBD and replicated three times using twenty-five senna accessions in the years 2020–21 and 2021–22. The combined ANOVA found that all fourteen of the traits studied were highly significant. The D2 analysis and λ1-λ2 values classified the 25 accessions into five clusters with 91.05 % diversity. The molecular diversity was also examined using SCoT markers. As SCoT markers target expressed portions of the genome, the variation among accessions reflects some of the morphological changes among them. For pharmaceutical applications, various lines Gen-1 and 2 (high in Sennosides A and B content) and Gen-4 can be hybridized with Gen-5 and 25 to produce generations high in pharmaceutically relevant Sennosides A and B. Considering genotypes Gen 1 and 2 rank first and second in terms of sennoside A and B contents in leaves (%) and pods, these two genotypes can be employed for large-scale cultivation and to transfer favorable traits in future breeding programs.

Kernel density estimation of allele frequency including undetected alleles.

Whereas undetected species contribute to estimation of species diversity, undetected alleles have not been used to estimated genetic diversity. Although random sampling guarantees unbiased estimation of allele frequency and genetic diversity measures, using undetected alleles may provide biased but more precise estimators useful for conservation. We newly devised kernel density estimation (KDE) for allele frequency including undetected alleles and tested it in estimation of allele frequency and nucleotide diversity using population generated by coalescent simulation as well as well as real population data. Contrary to expectations, nucleotide diversity estimated by KDE had worse bias and accuracy. Allele frequency estimated by KDE was also worse except when the sample size was small. These might be due to finity of population and/or the curse of dimensionality. In conclusion, KDE of allele frequency does not contribute to genetic diversity estimation.

Evaluation of non-additive genetic effects on carcass and meat quality traits in Korean Hanwoo cattle using genomic models

The traditional genetic evaluation methods generally consider additive genetic effects only and often ignore non-additive (dominance and epistasis) effects that may have contributed to genetic variation of complex traits of livestock species. The available dense single nucleotide polymorphisms (SNPs) panels offer to investigate the potential benefits of including non-additive genetic effects in the genomic evaluation models. Data from 16 971 genotyped (Illumina Bovine 50 K SNP chip) Korean Hanwoo cattle were used to estimate genetic variance components and prediction accuracy of genomic breeding values (GEBVs) for four carcass and meat quality traits: carcass weight (CWT), eye muscle area (EMA), back fat thickness (BFT) and marbling score (MS). Five different genetic models were evaluated through including additive, dominance and epistatic interactions (additive by additive, A × A; additive by dominance, A × D and dominance by dominance, D × D) successively in the models. The estimates of additive genetic variances and narrow sense heritabilities (ha2) were found similar across the evaluated models and traits except when additive interaction (A × A) was included. The dominance variance estimates relative to phenotypic variance ranged from 1.7–3.4% for CWT and MS traits, whereas, they were close to zero for EMA and BFT traits. The magnitude of A × A epistatic heritability (haa2) ranged between 14.8 and 27.7% in all traits. However, heritability estimates for A × D and D × D epistatic interactions (had2 and hdd2) were quite low compared to haa2 and were contributed only 0.0–9.7% of the total phenotypic variation. In general, broad sense heritability (hG2) estimates were almost twice (ranging between 0.54 and 0.68) the ha2 for all of the investigated traits. The inclusion of dominance effects did not improve the prediction accuracy of GEBV but improved 2.0–3.0% when epistatic effects were included in the model. More importantly, rank correlation revealed that partitioning of variance components considering dominance and epistatic effects in the model would enable to re-rank of top animals with better prediction of GEBV. The present result suggests that dominance and epistatic effects could be included in the genomic evaluation model for better estimates of variance components and more accurate prediction of GEBV for carcass and meat quality traits in Korean Hanwoo cattle.

Testing hypotheses of invasion pathways of the ladybird Harmonia axyridis into and across South Africa

Harmonia axyridis is an invasive beetle (Coleoptera: Coccinellidae), native to Asia, that has established on four continents beyond its native range and was first observed in South Africa in 2001. Using microsatellite data and a comprehensive geographic coverage of international (17 locations) and South African (14 locations) beetle samples, we inferred the source of colonists invading South Africa and the beetle’s movement within the country. Genetic structure analyses suggest that this species’ populations in South Africa are derived from admixture between beetles originating from eastern North America (which acted as a bridgehead population) and another population not directly sampled in our study. Genetic admixture prior its invasion into South Africa, along with the possibility of multiple introductions from the bridgehead population, may explain the high genetic diversity estimates for South African H. axyridis (HE = 0.582–0.625) compared to beetles from the native range (HE = 0.440–0.636). Harmonia axyridis appear to be frequently exchanging genetic material across South Africa, with no clear genetic structure between sampled locations. However, evidence of weak isolation-by-distance within South Africa suggests that beetles are dispersing less frequently between locations that are furthest apart. This study supports previous findings on global invasion pathways in this species but provides new insights in the context of the invasion in South Africa. We highlight how mixing of distinct lineages from divergent origins prior to the invasion into South Africa has augmented genetic diversity in the region. The high dispersal rates and large effective population sizes inferred from genetic markers suggest that slowing the spread or reducing population abundances of the species in South Africa will be challenging without an integrated, multi-faceted management approach.

Conservation genetics of the white-bellied pangolin in West Africa: A story of lineage admixture, declining demography, and wide sourcing by urban bushmeat markets.

During the last 40 years, the volumes of African pangolins feeding the illegal wildlife trade have dramatically increased. We conducted a conservation genetics survey of the most traded African species, the white bellied pangolin (WBP; Phataginus tricuspis), across three West African countries including Guinea, Côte d'Ivoire, and Ghana. Our study combining mitochondrial DNA sequencing and microsatellite genotyping is the first to reveal a wide pattern of admixture between two of the six mitochondrial lineages as previously delimited within WBP. We found a signature of isolation by distance but a lack of population genetic structuring, supporting the idea that WBP may have underestimated dispersal abilities. Levels of genetic diversity were low in West African lineages (WAfr and Gha) compared to Central Africa, reinforcing the picture of genetic pauperization shared by West African WBP. We observed a 85%-98% decline in the effective population size of WBP occurring c. 3200 to 400 ya, with current numbers (520-590) at the lower end of the conservative thresholds for minimum viable population size. The microsatellite markers were powerful enough to differentiate between individuals and identify replicated samples, confirming the utility of this approach in tracing the pangolin trade. Genetic diversity estimates confirmed that Yopougon, the main bushmeat market from Abidjan (Côte d'Ivoire), was fed by a large trade network as confirmed by vendors reporting 10 different sources situated 62-459 km away from the market. We conclude that WBP distributed in the Upper Guinean Block should be considered a single management unit of high conservation concern, as impacted by genetic diversity erosion, drastic decline in effective population size, and wide range sourcing for feeding urban bushmeat markets. Given the genetic admixture pattern detected within WBP from West Africa, we advocate for a multi-locus strategy to trace the international trade of the species.

Genetic diversity and autozygosity estimates in wild european boars and domesticated pigs

BACKGROUND: Pigs are one of the most widely distributed domestic animals. The study of their genetic diversity and selection loci is of great interest both in the field of genetics and animal breeding, and in the aspect of conservation and development of breeding resources and food security.&#x0D; AIM: The aim of the presented work is to evaluate the autozygosity and the distribution of autozygosity segments (HBD) in wild boars and pigs of the main commercial breeds: Large White, Landrace and Duroc, and to search for selection loci related to adaptation to habitat conditions and selection pressure.&#x0D; MATERIALS AND METHODS: The aim of the presented work is to evaluate the autozygosity and distribution of autozygosity segments (HBD) in wild boars and domestic pigs of the main commercial breeds: Large White, Landrace and Duroc, and to search for selection loci related to adaptation to habitat conditions and selection pressure.&#x0D; RESULTS: Based on the results of the genome scan, the average autozygosity values in boars and pigs were in the range of 0.23–0.29, but in boars about 0.08 of the genome share is covered by HBD segments, presumably originating from ancestors who lived about 206 years ago; in pigs — originating from ancestors who lived about 64 years ago.&#x0D; CONCLUSIONS: Only 3 segments met the criteria for top-HBD (frequency of at least 60% and at least 10 SNPs) in boars. In Large White, Landrace and Duroc pigs, 18, 9 and 35 segments were identified, respectively. In general, the analysis of HBD segments showed that they reflect the main breeding strategies aimed at developing commercial pigs.

Estimation of genetic diversity of the exotic Indian trout populations by using microsatellite markers

Estimation of genetic diversity of the exotic Indian trout populations by using microsatellite markers

Identification of Promising Sugarcane Clones Based on Cane Yield and Quality Traits in First Clonal Selection Stage

Sugarcane is a major source of sugar, facing constant pressure to enhance productivity due to the increased cost of cultivation and fluctuating global market prices. Identification of productive hybrid progenies for varietal development plays a crucial role in enhancing productivity, which is a cost-effective approach. In this context, an investigation was conducted to identify promising clones for cane yield and quality traits. Significantly higher estimates of genetic variability, heritability and genetic advance were evident for all the traits except cane girth, Brix per cent in juice and sucrose content in juice. Correlation and path analysis revealed that the traits such as the number of millable canes per plot, single cane weight, sucrose content in juice and commercial cane sugar yield showed a significant positive association with cane yield. Among the 150 hybrid progenies studied, the clones SNK 180011, SNK 180028, SNK 180070, SNK 180662 and SNK 181126 are the most promising clones with high cane yield and sugar productivity features. These results hold significant importance for identifying promising clones to enhance cane and sugar productivity.

The estimation of additive genetic variance of body size in a wild passerine is sensitive to the method used to estimate relatedness among the individuals.

Assessing additive genetic variance is a crucial step in predicting the evolutionary response of a target trait. However, the estimated genetic variance may be sensitive to the methodology used, e.g., the way relatedness is assessed among the individuals, especially in wild populations where social pedigrees can be inaccurate. To investigate this possibility, we investigated the additive genetic variance in tarsus length, a major proxy of skeletal body size in birds. The model species was the collared flycatcher (Ficedula albicollis), a socially monogamous but genetically polygamous migratory passerine. We used two relatedness matrices to estimate the genetic variance: (1) based solely on social links and (2) a genetic similarity matrix based on a large array of single-nucleotide polymorphisms (SNPs). Depending on the relatedness matrix considered, we found moderate to high additive genetic variance and heritability estimates for tarsus length. In particular, the heritability estimates were higher when obtained with the genetic similarity matrix instead of the social pedigree. Our results confirm the potential for this crucial trait to respond to selection and highlight methodological concerns when calculating additive genetic variance and heritability in phenotypic traits. We conclude that using a social pedigree instead of a genetic similarity matrix to estimate relatedness among individuals in a genetically polygamous wild population may significantly deflate the estimates of additive genetic variation.

Estimation of Genetic Diversity and Number of Unique Genotypes of Cassava Germplasm from Burkina Faso Using Microsatellite Markers.

Genetic diversity is very important in crop improvement. This study was carried out to assess the genetic diversity and the number of unique multilocus genotypes (MLGs) in a cassava collection in Burkina Faso. To achieve this objective, 130 cassava accessions were genotyped using 32 simple sequence repeat (SSR) markers. The results revealed that among these markers, twelve (12) were highly informative, with polymorphic information content (PIC) values greater than 0.50; twelve (12) were moderately informative, with PIC values ranging between 0.25 and 0.50; and eight (8) were not very informative, with PIC values lower than 0.25. A moderate level of genetic diversity was found for the population, indicated by the average expected heterozygosity (0.45) and the observed heterozygosity (0.48). About 83.8% of unique multilocus genotypes were found in the cassava collection, indicating that SSR markers seem to be most appropriate for MLG identification. Population structure analysis based on hierarchical clustering identified two subpopulations and the Bayesian approach suggested five clusters. Additionally, discriminant analysis of principal components (DAPC) separated the cassava accessions into 13 subpopulations. A comparison of these results and those of a previous study using single nucleotide polymorphisms (SNP) suggests that each type of marker can be used to assess the genetic structure of cassava grown in Burkina Faso.

Estimation of Genetic Variability in Relation to Heterosis and Combining Ability of Wheat from Subtropical and Temperate Zones

Estimation of Genetic Variability in Relation to Heterosis and Combining Ability of Wheat from Subtropical and Temperate Zones

Investigating the impact of non-additive genetic effects in the estimation of variance components and genomic predictions for heat tolerance and performance traits in crossbred and purebred pig populations

BackgroundNon-additive genetic effects are often ignored in livestock genetic evaluations. However, fitting them in the models could improve the accuracy of genomic breeding values. Furthermore, non-additive genetic effects contribute to heterosis, which could be optimized through mating designs. Traits related to fitness and adaptation, such as heat tolerance, tend to be more influenced by non-additive genetic effects. In this context, the primary objectives of this study were to estimate variance components and assess the predictive performance of genomic prediction of breeding values based on alternative models and two independent datasets, including performance records from a purebred pig population and heat tolerance indicators recorded in crossbred lactating sows.ResultsIncluding non-additive genetic effects when modelling performance traits in purebred pigs had no effect on the residual variance estimates for most of the traits, but lower additive genetic variances were observed, especially when additive-by-additive epistasis was included in the models. Furthermore, including non-additive genetic effects did not improve the prediction accuracy of genomic breeding values, but there was animal re-ranking across the models. For the heat tolerance indicators recorded in a crossbred population, most traits had small non-additive genetic variance with large standard error estimates. Nevertheless, panting score and hair density presented substantial additive-by-additive epistatic variance. Panting score had an epistatic variance estimate of 0.1379, which accounted for 82.22% of the total genetic variance. For hair density, the epistatic variance estimates ranged from 0.1745 to 0.1845, which represent 64.95–69.59% of the total genetic variance.ConclusionsIncluding non-additive genetic effects in the models did not improve the accuracy of genomic breeding values for performance traits in purebred pigs, but there was substantial re-ranking of selection candidates depending on the model fitted. Except for panting score and hair density, low non-additive genetic variance estimates were observed for heat tolerance indicators in crossbred pigs.

Risk factors and genetic parameters of longevity in Spanish dairy goat breeds using a Weibull proportional hazards model

The aim of this study was to assess the most important risk factors that influence productive life (PL) and to estimate genetic parameters for PL using a Weibull proportional hazards model in two Spanish dairy goat breeds belonging to different production systems. The dataset consisted of 70,695 and 49,176 lactation records of Florida and Payoya females, respectively, collected over the last two decades. A total of 6,227 (24.21%) Florida and 3,452 (20.42%) Payoya females had censored information. The pedigree included a total of 56,901 animals for Florida and 59,957 for Payoya. The effects included in the model for both breeds were the age at first kidding and the herd-year-season of birth of the doe as time-independent effects; and the age at kidding, the herd-year-season of kidding, the within-herd class of milk production deviation and the combination between the lactation number and the duration of lactation as time-dependent effects. Estimation of genetic parameters was made using a Weibull proportional hazards model using Survival Kit V6.0 software. The results from the Weibull animal models gave estimates of additive genetic variances of 0.99 ± 0.0003 and 0.156 ± 0.021, which corresponds to a heritability of 0.43 ± 0.025 and 0.11 ± 0.021 for Florida and Payoya, respectively. The magnitude of heritability obtained for PL suggests that a substantial response to selection may be expected for longevity, especially in the Florida breed. These results may contribute to the development of a routine genetic evaluation to improve PL in Spanish dairy goat breeds.

Estimation of genetic variability and correlation coefficients of different salinity levels in mungbean genotypes

For this study eight mungbean genotypes viz., ADT 2, BM-2002-1, ML 5, AKM 4, Vishal, Vamban, TARM 1 and Utkarsh were used. Observation were taken on seven seedling characters and 7 quantitative characters. Statistical analysis of the seedling and quantitative characters showed that the PCV was higher than that of GCV for all the characters studied. Highest GCV and PCV were expressed by seedling shoot dry weight at 6 dSm-1 salinity level followed by seedling shoot fresh weight at 6 dSm-1, indicating that variation among the genotypes was highest for these traits. The PCV and GCV values were lowest in germination percentage followed by the shoot length at control. Among the growth characters heritability (broad sense) was found to range from 41.57 % to 100 % in control, while in salinity levels broad sense heritability ranged from 50 % to 100 %. Under control, heritability was high for all characters except for germination percentage, shoot length and plant height. While in salinity condition, it was high for all characters except for number of pods/plant at 6 dsm-1 salinity level. The genetic advance was high in nature only for the germination percentage whereas, the remaining character revealed low GA estimates. The maximum genetic advance in percent of mean (GAMP) was obtained for seedling shoot dry weight followed by seedling root dry weight at 6 dsm-1 and the lowest was for plant height followed by germination percentage at control. The study revealed that all the 14 characters were positively correlated with each other. For all the characters, the genotypic correlation was at higher level than the phenotypic correlation. Four elite genotypes were found to be superior based on the mean performance namely Utkarsh, TARM 1, Vamban and Vishal among the various levels of salinity.

Assessment of Variability, Heritability and Genetic Advance in 31 Genotypes of Gladiolus (Gladiolus grandifloras L.)

In this study, 31 genotypes of gladiolus were examined to provide estimates of genetic variability, analysis of variance, genetic parameters (GCV, PCV, heritability and genetic progress) for thirteen different characters. The research trial was conducted at the crop research Center, Department of Genetics and Plant Breeding, School of Agriculture, ITM University, Gwalior, Madhya Pradesh using RBD design. According to the analysis of variance, 31 genotypes had notable variations for each character. Heritability estimates ranged from 22% to 99%. While the highest heritability 99% was predicted for the spike initiation, the character number of shoots per corm was expected to have the lowest heritability 22.76%. The percentage of genetic advances ranges from 24.25% to 69.41% of the mean. The highest and lowest percentages of the mean genetic advance were found for plant height 51.77% and the number of shoots per corm 0.79% .

Estimation of genetic parameters and variability of various cayenne peppers under net shading

Abstract. Siahaan GF, Chozin MA, Syukur M, Ritonga AW. 2023. Estimation of genetic parameters and variability of various cayenne peppers under net shading. Biodiversitas 24: 5912-5919. The intercropping systems are important concerning the decreasing agricultural land and the increasing population. Chili could be planted as intercrops, but not all chili genotypes were adapted to low light-intensity stress. This study aims to determine the genetic diversity of cayenne pepper under 50% plastic net shade conditions based on morphological and agronomic traits. The study was conducted at the Cikabayan Experimental Field, Institut Pertanian Bogor, Dramaga, Bogor, from January to July 2021. The genetic material consisted of ten genotypes of cayenne pepper from Capsicum annuum L. and ten from Capsicum frustescens L.. Each genotype of chili was planted with three replications, so there were 60 experimental units. Each experimental unit consisted of six plants planted in an area of 1.5 m2. The shade used was a plastic net shade with a 50% shading level. The estimation of genetic parameters showed that leaf area, number of leaves, fruit weight, number of fruits, and yield per plant had a high genotypic coefficient of variation (GCV) and broad-sense heritability (Hbs). Cluster analysis resulted in two main clusters based on twelve chili growth and agronomic characters. All chili genotypes included in Cluster 1 were C. annuum chilies. On the other hand, all the chili genotypes in Cluster 2 were C. frutescens chilies except for the G19 genotype. Cayenne pepper in Cluster 2 had a higher number of leaves, plant height, stem diameter, leaf area, fruit diameter, pedicle length, fruit weight, number of fruits, and yield per plant than cayenne pepper in Cluster 1. The result of this study indicates that C. frutescens cayenne pepper has more potential to be planted under shading conditions and used in intercropping than C. annuum.

Unravelling the genetic variability of host resilience to endo- and ectoparasites in Nellore commercial herds

BackgroundHost resilience (HR) to parasites can affect the performance of animals. Therefore, the aim of this study was to present a detailed investigation of the genetic mechanisms of HR to ticks (TICK), gastrointestinal nematodes (GIN), and Eimeria spp. (EIM) in Nellore cattle that were raised under natural infestation and a prophylactic parasite control strategy. In our study, HR was defined as the slope coefficient of body weight (BW) when TICK, GIN, and EIM burdens were used as environmental gradients in random regression models. In total, 1712 animals were evaluated at five measurement events (ME) at an average age of 331, 385, 443, 498, and 555 days, which generated 7307 body weight (BW) records. Of the 1712 animals, 1075 genotyped animals were used in genome-wide association studies to identify genomic regions associated with HR.ResultsPosterior means of the heritability estimates for BW ranged from 0.09 to 0.54 across parasites and ME. The single nucleotide polymorphism (SNP)-derived heritability for BW at each ME ranged from a low (0.09 at ME.331) to a moderate value (0.23 at ME.555). Those estimates show that genetic progress can be achieved for BW through selection. Both genetic and genomic associations between BW and HR to TICK, GIN, and EIM confirmed that parasite infestation impacted the performance of animals. Selection for BW under an environment with a controlled parasite burden is an alternative to improve both, BW and HR. There was no impact of age of measurement on the estimates of genetic variance for HR. Five quantitative trait loci (QTL) were associated with HR to EIM but none with HR to TICK and to GIN. These QTL contain genes that were previously shown to be associated with the production of antibody modulators and chemokines that are released in the intestinal epithelium.ConclusionsSelection for BW under natural infestation and controlled parasite burden, via prophylactic parasite control, contributes to the identification of animals that are resilient to nematodes and Eimeria ssp. Although we verified that sufficient genetic variation existed for HR, we did not find any genes associated with mechanisms that could justify the expression of HR to TICK and GIN.