ARTICLE 1 – research

OPTIMIZATION OF ANCESTRY INFORMATIVE MARKERS (AIMS) TO CHARACTERIZE THE COMPOSITION OF THE ARGENTINE POPULATION

OPTIMIZACIÓN DE MARCADORES INFORMATIVOS DE ANCESTRÍA (AIMS) PARA CARACTERIZAR LA COMPOSICIÓN DE LA POBLACIÓN ARGENTINA

Patiño J., Lozano M., Russo M.G., Dejean C.B., Avena S.

The Argentine population exhibits a complex genetic structure resulting from historical admixture processes among Western Eurasian, Indigenous, and Sub-Saharan African components, with marked regional variations across the country. To characterize the population composition of the Buenos Aires Metropolitan Area (AMBA), we optimized a panel of 30 ancestry informative markers (AIMs), combining multiplex APLP-PCR, RFLP-PCR, and Alu insertion techniques. We analyzed 50 unrelated blood donor samples from public and private hospitals, using STRUCTURE and ADMIX programs to estimate ancestral contributions at the individual and population levels. Results showed predominance of the Western Eurasian component (84.0%), followed by Indigenous (12.5%) and Sub-Saharan African (3.4%) ancestries. Through technique optimization and standardization, we excluded five AIMs in Hardy-Weinberg disequilibrium; various tests confirmed that this exclusion did not significantly alter the estimates, validating the panel’s robustness. This work demonstrates that the selected 30 AIMs provide reliable ancestry estimates in admixed populations, offering a cost-effective and highly efficient molecular tool for determining individual and population genetic ancestry that overcomes the limitations of previous methods based on varying marker quantity and quality. Notably, these applications extend beyond biological anthropology, as local ancestry identification is also relevant for biomedical and pharmacogenetic studies in Argentina, where European homogeneity is often erroneously assumed.

Key words: genetic diversity, autosomal markers, admixture
Language: Spanish

ARTICLE 2 – research

CARACTERIZACIÓN MORFOLÓGICA Y MOLECULAR DE UNA COLECCIÓN DE GERMOPLASMA DE Stevia rebaudiana BERT.

MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF A GERMPLASM COLLECTION OF Stevia rebaudiana BERT.

Budeguer C.J., Erazzú L.E., Camadro E.L.

Stevia rebaudiana Bertoni (Asteraceae) (2n=2x=22) is a species native from Paraguay where it is known as Ka’a-He-é (sweet herb) because of the intense sweet flavor of its leaves. Such flavor is due to a series of diterpene glycosides or steviol glycosides, mainly stevioside and rebaudioside-A, which are 300 and 400 times sweeter than sucrose. This species is cultivated for the industrial obtainment of steviol glycoside crystals, utilized as dietary natural sweeteners, and dry leaves for adding to food. To establish an active S. rebaudiana gene bank for breeding purposes, plants from four Argentinian provinces were introduced in EEA Famaillá, INTA, Tucumán, in 2013 and 2021 -two introductions per province from Tucumán, Jujuy, and Misiones, and one from Formosa-. Of these, 75 were subjected to morphological characterization and 73 to molecular characterization using 18 EST-SSR. In the multivariate analysis for morphological traits, measures overlapped in the introductions from Tucumán, Jujuy, and Misiones, whereas the introduction from Formosa differed from the rest in leaf size and plant height. In the molecular analysis, the introductions exhibited diversity for number of alleles, heterozygosis, and percentage of polymorphic loci, except for the introduction from Formosa, which presented uniform molecular profiles. In the analysis of the molecular variance (AMOVA), 77% of the total variation corresponded to differences among plants within introductions, 15% to differences among provinces (geographical origin), and 8% to differences among introductions within provinces. The observed morphological variability and molecular diversity allow to conclude that the analyzed S. rebaudiana germplasm could be of value to initiate a breeding program.

Key words: EST-SSR molecular markers, genetic diversity, morphological variability, Stevia
Language: Spanish

ARTICLE 3 – research

ESTUDIO DE LA EXPRESIÓN GÉNICA DIFERENCIAL EN VACAS LECHERAS EN EL PERIODO DE TRANSICIÓN CON ALTA Y BAJA ACTIVIDAD DE GLUTATIÓN PEROXIDASA

STUDY OF DIFFERENTIAL GENE EXPRESSION DURING THE TRANSITION PERIOD OF DAIRY COWS WITH HIGH AND LOW GLUTATHIONE PEROXIDASE ACTIVITY

Calcaterra F., Fernandez M.E., Marcuzzi O., Olivera L.H., Peral García P., Picco S.J, Giovambattista G

Glutathione peroxidase (GSHpx) is a selenium-dependent enzyme that helps protect cells from oxidative stress by reduction of H₂O₂ to H₂O. The objective of this study was to evaluate the association between GSHpx activity levels, which is commonly used as an indicator of selenium status, and gene expression profiles in peripheral blood of transition dairy cattle. The study was carried out in a commercial dairy farm of Holstein cattle, seven days after calving, blood samples were obtained from the jugular vein of randomly selected animals (n = 12). GSHpx activity was determined and animals were separated into two significantly different groups according to measured levels, in one group those with lower levels of activity (G1) and in the other those with higher activity (G2). Bulk RNA-seq analysis of peripheral blood cells resulted in 1,044 differentially expressed genes (DEGs). Functional enrichment and ontology analyses revealed 21 and 26 significant KEGG pathways and GO terms, respectively (p_adjusted < 0.01). To evaluate the robustness of these findings, milk production was included as a covariate and Venn diagram analysis showed that the majority of the initial DEGs, GO terms, and KEGG pathways were consistently shared between both models. I-cisTarget analysis revealed 431 enriched features (NES >3), which were associated with transcription factors, cofactors and epigenetic changes. In conclusion, differences in GSHpx activity levels, which can be associated with differences in selenium levels, lead to an elevated number of DEGs, KEGG pathways, GO terms, epigenetic and regulatory changes, which were associated with the functioning of the immune system and the inflammatory response. These results could be indicative of different physiological adaptations.

Key words: Oxidative stress, GSHpx, Dairy cattle, Holstein, Transcriptome, Peripartum period
Language: English

ARTICLE 4 – research

ESTADO ACTUAL DE LA APLICACIÓN DE TECNOLOGÍA GENÓMICA EN BOVINOS PARA CARNE DE ARGENTINA

CURRENT STATUS OF THE APPLICATION OF GENOMIC TECHNOLOGY IN BEEF CATTLE OF ARGENTINA

Corva, P.M., Pardo, A.M., Martínez, M.

This article examines the evolution and status of genomic technology applied to beef cattle in Argentina. The review is organized into three areas of application: breed identification and parentage verification, detection of carriers of deleterious genetic variants and marker-assisted selection (MAS) and genomic selection. In breed identification and parentage control, the transition from microsatellites to SNP panels is becoming the standard procedure, improving genealogical integrity and expanding applications such as breed certification, traceability and cattle rustling. The review also addresses the use of genomics for the detection of Mendelian variants, which makes it possible to identify carriers, guide mating decisions and reduce the impact of hereditary defects. Finally, the transition from selection strategies based on a limited number of markers (MAS) to genomic prediction schemes is reviewed. MAS had limited adoption due to its low capacity to capture the genetic variation of complex polygenic traits, whereas genomic selection became established in leading breeds when medium-density genotyping, sufficiently large reference populations, and integrated methodologies converged. Unlike dairy cattle, there is still no clear evidence of the advantage gained with genomic selection in beef cattle. The Argentine experience shows that the contribution of genomics has been effective but not uniform across applications: it constitutes a consolidated tool for parentage confirmation and management of deleterious variants, whereas its potential in selection still depends on strengthening recording systems, phenotyping/genotyping, validation, and institutional coordination supporting its use.

Key words: SNP arrays, parentage verification, carriers, genomic selection
Language: Spanish