Xochitl F De la Rosa-Reyna

Genetic diversity and structure among subspecies of white-tailed deer in Mexico

Abstract The white-tailed deer (Odocoileus virginianus) occurs over a broad latitudinal range from South America to Canada. Thirty-eight subspecies are recognized, 14 of which occur in Mexico. Genetic studies in Latin America are lacking and the diversity and structure of white-tailed deer in Mexico are unknown. We sampled white-tailed deer from 13 sites in the range of 5 subspecies occurring in Mexico, O. v. texanus, O. v. carminis, O. v. veraecrucis, O. v. sinaloae, and O. v. yucatanensis. We estimated genetic diversity and structure based on 12 microsatellite DNA loci. Observed heterozygosity (HO) was comparable to that of white-tailed deer in the United States (HO = 0.53–0.64), with the exception of O. v. yucatanensis (HO = 0.41). We observed statistically significant genetic structure among all 13 sites (FST = 0.15). Analysis of molecular variance revealed that grouping sites by subspecies (FSC = 0.09) or geographic region (FSC = 0.13–0.14) explained a moderate portion of genetic variation. However, no higher-level group minimized differentiation among populations within the subspecies or regional groups (FST = 0.16–0.20). Pairwise genetic distances among sites were correlated with geographic distance (r2 = 0.38), but some geographically proximate sites were genetically differentiated (FST > 0.20), especially in the Yucatan. Deer in the Yucatan were genetically differentiated from other subspecies and had comparatively lower genetic diversity, consistent with the biogeographic history of the region. Populations of white-tailed deer in Mexico are subject to a range of management challenges. Additional research is needed to understand the effect of management on the diversity and genetic structure of white-tailed deer. Resumen El venado de cola blanca (Odocoileus virginianus) se distribuye en un amplio rango latitudinal desde el sur de América hasta Canadá. De las 38 subespecies reconocidas, 14 habitan en México. Debido al número limitado de estudios genéticos en Latinoamérica, la diversidad y estructura poblacional del venado de cola blanca en México es desconocida. En este estudio, muestreamos venado de cola blanca de 13 sitios ubicados dentro del rango de distribución de 5 subespecies de México, O. v. texanus, O. v. carminis, O. v. veraecrucis, O. v. sinaloae, and O. v. yucatanensis. La diversidad y estructura genética fue estimada con 12 marcadores microsatélites. La heterocigosidad observada fue comparable a lo observado en el venado de cola blanca de Norteamérica (HO = 0.53–0.64), con excepción de O. v. yucatanensis (HO = 0.41). Se observó una estructura genética significativa entre los 13 sitios de muestreo (FST = 0.15). El análisis de varianza molecular reveló que los sitios de muestreo agrupados por subespecie (FSC = 0.09) o región geográfica (FSC = 0.13–0.14) explicaron una porción moderada de la variación genética. Sin embargo, la diferenciación entre las poblaciones no fue minimizada a un nivel de agrupamiento mayor, es decir dentro de subespecies o grupos regionales (FST = 0.16–0.20). La distancia genética entre sitios de muestreo estuvo correlacionada con la distancia geográfica (r2 = 0.38), pero algunos sitios geográficamente próximos estuvieron genéticamente diferenciados (FST > 0.20), especialmente en Yucatán. El venado de cola blanca de Yucatán fue diferenciado genéticamente de las otras subespecies y fue comparativamente el de menor diversidad genética, lo cual es consistente con la historia biogeográfica de la región. Las poblaciones de venado cola blanca en México están sujetas a diversos retos de manejo. Por lo tanto, se requiere de investigación adicional para comprender el efecto sobre su diversidad y estructura genética.

Microsatellite polymorphism in intron 1 of the bovine myostatin gene.

Microsatellites within genes have become important because of their association with genetic diseases in humans. A novel microsatellite was identified in the first intron of the bovine myostatin gene. It is characterized by a mononucleotide core motif that exhibits polymorphic sequence variants (from 12 to 21 repeats) within and between some bovine breeds. Structural analysis of the microsatellite region in bovines as well as in closely related species permitted to trace the possible mechanisms for its structural evolution across the order Artiodactyla.

Genetic diversity of tyrosine hydroxylase (TH) and dopamine b-hydroxylase (DBH) genes in cattle breeds

DNA from four cattle breeds was used to re-sequence all of the exons and 56% of the introns of the bovine tyrosine hydroxylase (TH) gene and 97% and 13% of the bovine dopamine β-hydroxylase (DBH) coding and non-coding sequences, respectively. Two novel single nucleotide polymorphisms (SNPs) and a microsatellite motif were found in the TH sequences. The DBH sequences contained 62 nucleotide changes, including eight non-synonymous SNPs (nsSNPs) that are of particular interest because they may alter protein function and therefore affect the phenotype. These DBH nsSNPs resulted in amino acid substitutions that were predicted to destabilize the protein structure. Six SNPs (one from TH and five from DBH non-synonymous SNPs) were genotyped in 140 animals; all of them were polymorphic and had a minor allele frequency of > 9%. There were significant differences in the intra- and inter-population haplotype distributions. The haplotype differences between Brahman cattle and the three B. t. taurus breeds (Charolais, Holstein and Lidia) were interesting from a behavioural point of view because of the differences in temperament between these breeds.

Genetic shifts in the transition from wild to farmed white-tailed deer (Odocoileus virginianus) population

The white-tailed deer (Odocoileus virginianus) is one of the most important species related to sport hunting in northern Mexico. During the last decade, this species has been subjected to intensive breeding to achieve improvements in certain desired traits (i.e., antlers). This alleged intensive management of bringing originally wild populations into captivity might have harmful consequences on genetic diversity. In this short research paper we estimate and discuss the consequences of that transition, as assessed by a microsatellite genetic marker analysis. The results show that no short-term changes in genetic diversity parameters were promoted by captivity; however, a genetic diversity condition maintained by artificial genetic flow was identified, perhaps allowing for the required introgression of gene diversity into this closed population. A wider analysis is recommended and the implications are discussed. Within a realistic forecast of expanding sport hunting, the achievement of useful, pragmatic, and strict conservancy programs of this species, considering approaches such as those used here, will be necessary.

The complete mitochondrial genomes of nine white-tailed deer subspecies and their genomic differences

The white-tailed deer (Odocoileus virginianus) is an important, sustainable-use species in Mexico; 14 subspecies are widely distributed throughout the Mexican territory. The criteria for classifying subspecies is based on morphological features throughout their geographical range; however, the complete genetic characterization of Mexican subspecies has not been established. The objective of the present work is to report the mitogenomes of 9 of the 14 white-tailed deer subspecies from Mexico and identify their unique variations. Typical vertebrate mitogenomes structures (i.e., 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes) were observed in the studied subspecies. The greatest numbers of polymorphisms were identified in the D-loop, ND4, ND5, CYTB/ COI, ATP6, and COIII genes. Phylogenetic analyses showed that the southern and southeastern subspecies were distinct from the central and northern subspecies; the greatest genetic distances were also observed between these 2 groups. These subspecies-specific variations could be useful for designing a strategy to genetically characterize the studied subspecies.

Assessment of the myostatin Q204X allele using an allelic discrimination assay

An allelic discrimination assay was designed and used to determine the genotypic and allelic frequencies of the myostatin (MSTN) gene Q204X allele from two Mexican Full-French herds. The assay is a simple high throughput genotyping method that could be applied to investigate the effect of the Q204X allele on the Charolais breed.