María Victoria Arruga

Localisation of aphidicolin-induced break points in Holstein-Friesian cattle (Bos taurus) using RBG-banding

Fragile sites (FS) seem to play a role in genome instability and may be involved in karyotype evolution and chromosome aberrations. The majority of common fragile sites are induced by aphidicolin. Aphidicolin was used at two different concentrations (0.15 and 0.30 μM) to study the occurrence of FS in the cattle karyotype. In this paper, a map of aphidicolin induced break points and fragile sites in cattle chromosomes was constructed. The statistical analysis indicated that any band with three or more breaks was significantly damaged (P < 0.05). According to this result, 30 of the 72 different break points observed were scored as fragile sites. The Pearson correlation test showed a positive association between chromosome length and the number of fragile sites (r = 0.54). On the contrary, 21 FS were identified on negative R bands while 9 FS were located on positive R bands.

Comparison of different procedures of DNA analysis for sex identification in the endangered bearded vulture (Gypaetus barbatus)

During the last century, bearded vulture populations have declined and are threatened by extinction in Europe. Conservation efforts such as captive-bird breeding programs require the knowledge of the sex of individuals. The bearded vulture is difficult to sex morphologically because it is sexually monomorphic. Until now, there were no published genetic methods to sex this species. In our study, we tested different methods based on polymerase chain reaction analysis of the chromobox-helicase-DNA binding protein gene. This gene is located on both sex chromosomes, but the two copies differ in size depending on chromosomal location. Differences can be detected by digestion with restriction enzymes or with the amplification refractory mutation system technique. These methods are quick, accurate, and inexpensive and allow a large scale sex typing of bearded vultures.

Genetic variability and population structure in Cypriot chukar partridges (Alectorischukar cypriotes) as determined by microsatellite analysis

For the first time, microsatellite loci were used to study the genetic structure in Alectoris chukar cypriotes. Four of the ten tested microsatellite loci were found to be polymorphic in 33 individuals from four regions of Cyprus. The differentiation test between all the pairs of samples gave non-differentiation exact P values in every case (P>0.05). The posterior probability distribution on the number of source populations indicated only one population (P=0.977); also, a high Bayes factor value (130.020) was obtained. Posterior co-assignment probabilities (measures of similarity) for all pairs of individuals ranged from 0.984 to 1. The global FIS value was not found to be significant. A recent bottleneck of the Cypriot total partridge population is suggested and this is supported by a significant Wilcoxon test (P=0.031) under the Infinite Alleles Model (IAM) and shifted mode in the alleles frequencies distribution. The results suggest that all the individuals studied belong to only one randomly mating (panmictic) population, with low genetic variation and evidence of recent effective population size reduction (genetic bottleneck). A big hunting pressure exists on the island and about 200,000 captive-bred birds are released every year; these individuals are descendant from a small number of eggs collected in a small area of Cyprus in 1986 and this founder effect could explain the existence of a bottleneck and the low genetic variability.

Assignment of two markers carried by human chromosome 1 to different cattle synteny groups: FH to U1 and PEPC to U17 (chromosome 8)

Two loci located on human chromosome 1 were mapped in cattle by means of interspecific (hamster x cattle) somatic cell hybridization. FH is assigned to the U1 synteny group together with PGD, ENO1, AT3, and REN, while PEPC is found to belong to the U17 group (chromosome 8), like FN1, CRYG, and VIL1.

Microsatellite characterization of Cimarron Uruguayo dogs

Various genetic markers, including microsatellites, have been used to analyze the genetic polymorphism and heterozygosity in canine breeds. In this work, we used nine microsatellite markers to investigate the genetic variability in Cimarron Uruguayo dogs, the only officially recognized native canine breed in Uruguay. DNA from 30 Cimarron Uruguayo dogs from northeastern and southern Uruguay was analyzed. The allelic frequencies for each microsatellite, the genetic variability and the consanguinity were calculated, as were the polymorphic information content (PIC) and the probability of exclusion (PE). All of the microsatellites studied were polymorphic. FH 2361, FH 2305 and PEZ 03 were the most informative, with PIC values > 0.7, in agreement with results for other canine breeds. The PE values for the markers were within the ranges previously described and were generally greater for microsatellites with higher PIC values. The heterozygosity value (0.649) was considered high since only nine microsatellites were analyzed. Compared with data for other breeds, the results obtained here indicate that Cimarron Uruguayo dogs have high genetic diversity.

The present Pyrenean population of bearded vulture (Gypaetus barbatus): Its genetic characteristics

The Pyrenean population of the endangered bearded vulture (Gypaetus barbatus) is the largest natural population in Europe. In this study, its current genetic variability was assessed using 110 animals of the recent population in order to know what the present situation. Sex identification by DNA methodology in the 110 bearded vultures, mitochondrial DNA (mtDNA) and eight microsatellite markers in 87 bearded vultures have been analysed. Our results for sex identification present a number of 49 males and 61 females; no significant differences for number of males and females in this population have been observed. mtDNA studies indicate that nucleotide and haplotype diversities and number of variable sites were low. Tajima’s D test and Fu and Li’s D* and F* tests suggest that mutations are selectively neutral and the population is expanding. A mean number of alleles per locus and a mean observed heterozygosity have been obtained by microsatellite analysis. FIS is not high, and inbreeding depression could be discarded in the near future. The results suggest that the Pyrenean population of bearded vultures have to be controlled in order to avoid the loss of genetic variability. This data should be taken into account when considering conservation plans for the species.

A comparative genetic study of two groups of chukar partridges (Alectoris chukar) from Cyprus and Argentina, using microsatellite analysis

The aim of the present work is to estimate the usefulness of microsatellite genetic markers analysis to characterize and analyze the possible differences between a captive reared population and a wild one from the same species. The first sample consists of 27 chukar partridges (Alectoris chukar) bred in one farm in Argentina. The second one is composed of 31 chukar partridges coming from a wild Cyprus population (A. chukar cypriotes). We analyzed seven microsatellite loci: MCW135, MCW225, MCW276, MCW280, MCW295, LEI31, and ADL0142. The Argentina group showed higher genetic variation than the Cyprus did. Significant global FIS value was found in the Argentina sample. Significant genetic differentiation exists between both groups (FST=0.394; p<0.01). The Argentina group did not show any signs of bottleneck. Results from Factorial Correspondence Analysis (FCA) suggest that the 58 partridges could be split into two distinct genetic clusters (Cyprus and Argentina). Nevertheless, in the light of PARTITION results, three Argentina individuals might be related to Cyprus. STRUCTURE is unable to assign these three animals to any of the two groups. This could be due to a single or repeated introduction of external individuals into the original Argentina group, so that these results would point to more than one origin for this population. This admixture of individuals could explain the high genetic variation observed in the Argentina farm. Global FIS value would probably be higher without these immigrations; on the other hand, these admixtures could have prevented bottlenecks.

Estudios preliminares de la estructura genética del perro cimarrón uruguayo usando microsatélites

Analizar la estructura poblacional en una muestra de perros “Cimarron Uruguayo” usando marcadores moleculares tipo microsatelites. Materiales y metodos. Se analizaron treinta caninos de diferentes zonas de Uruguay con un set de nueve marcadores moleculares microsatelites empleando PCR. La estructura poblacional se analizo con el software de distribucion libre “Structure”. Resultados. Segun nuestros datos, los resultados preliminares muestran que no es posible establecer una subdivision entre los animales de la muestra. Conclusiones. El estudio realizado apoya la hipotesis de que los perros que existen en la actualidad derivan del nucleo fundador que se refugio en la region noreste del pais. La distribucion de la raza entre las distintas areas de Uruguay continua hoy en dia, no existe aislamiento entre los diferentes grupos de animales y el intercambio es constante.