Dissection of ancestral genetic contributions to Creole goat populations.

Goats have played a key role as source of nourishment for humans in their expansion all over the world in long land and sea trips. This has guaranteed a place for this species in the important and rapid episode of livestock expansion triggered by Columbus' arrival in the Americas in the late 1400s. The aims of this study are to provide a comprehensive perspective on genetic diversity in American goat populations and to assess their origins and evolutionary trajectories. This was achieved by combining data from autosomal neutral genetic markers obtained in more than two thousand samples that encompass a wide range of Iberian, African and Creole goat breeds. In general, even though Creole populations differ clearly from each other, they lack a strong geographical pattern of differentiation, such that populations of different admixed ancestry share relatively close locations throughout the large geographical range included in this study. Important Iberian signatures were detected in most Creole populations studied, and many of them, particularly the Cuban Creole, also revealed an important contribution of African breeds. On the other hand, the Brazilian breeds showed a particular genetic structure and were clearly separated from the other Creole populations, with some influence from Cape Verde goats. These results provide a comprehensive characterisation of the present structure of goat genetic diversity, and a dissection of the Iberian and African influences that gave origin to different Creole caprine breeds, disentangling an important part of their evolutionary history. Creole breeds constitute an important reservoir of genetic diversity that justifies the development of appropriate management systems aimed at improving performance without loss of genomic diversity.

Genetic diversity and patterns of population structure in Creole goats from the Americas.

Biodiversity studies are more efficient when large numbers of breeds belonging to several countries are involved, as they allow for an in-depth analysis of the within- and between-breed components of genetic diversity. A set of 21 microsatellites was used to investigate the genetic composition of 24 Creole goat breeds (910 animals) from 10 countries to estimate levels of genetic variability, infer population structure and understand genetic relationships among populations across the American continent. Three commercial transboundary breeds were included in the analyses to investigate admixture with Creole goats. Overall, the genetic diversity of Creole populations (mean number of alleles = 5.82 ± 1.14, observed heterozygosity = 0.585 ± 0.074) was moderate and slightly lower than what was detected in other studies with breeds from other regions. The Bayesian clustering analysis without prior information on source populations identified 22 breed clusters. Three groups comprised more than one population, namely from Brazil (Azul and Graúna; Moxotó and Repartida) and Argentina (Long and shorthair Chilluda, Pampeana Colorada and Angora-type goat). Substructure was found in Criolla Paraguaya. When prior information on sample origin was considered, 92% of the individuals were assigned to the source population (threshold q ≥ 0.700). Creole breeds are well-differentiated entities (mean coefficient of genetic differentiation = 0.111 ± 0.048, with the exception of isolated island populations). Dilution from admixture with commercial transboundary breeds appears to be negligible. Significant levels of inbreeding were detected (inbreeding coefficient > 0 in most Creole goat populations, P < 0.05). Our results provide a broad perspective on the extant genetic diversity of Creole goats, however further studies are needed to understand whether the observed geographical patterns of population structure may reflect the mode of goat colonization in the Americas.

Conservation priorities of Iberoamerican pig breeds and their ancestors based on microsatellite information.

Criollo pig breeds are descendants from pigs brought to the American continent starting with Columbus second trip in 1493. Pigs currently play a key role in social economy and community cultural identity in Latin America. The aim of this study was to establish conservation priorities among a comprehensive group of Criollo pig breeds based on a set of 24 microsatellite markers and using different criteria. Spain and Portugal pig breeds, wild boar populations of different European geographic origins and commercial pig breeds were included in the analysis as potential genetic influences in the development of Criollo pig breeds. Different methods, differing in the weight given to within- and between-breed genetic variability, were used in order to estimate the contribution of each breed to global genetic diversity. As expected, the partial contribution to total heterozygosity gave high priority to Criollo pig breeds, whereas Weitzman procedures prioritized Iberian Peninsula breeds. With the combined within- and between-breed approaches, different conservation priorities were achieved. The Core Set methodologies highly prioritized Criollo pig breeds (Cr. Boliviano, Cr. Pacifico, Cr. Cubano and Cr. Guadalupe). However, weighing the between- and within-breed components with FST and 1-FST, respectively, resulted in higher contributions of Iberian breeds. In spite of the different conservation priorities according to the methodology used, other factors in addition to genetic information also need to be considered in conservation programmes, such as the economic, cultural or historical value of the breeds involved.

Genetic characterization of Latin-American Creole cattle using microsatellite markers.

Genetic diversity in and relationships among 26 Creole cattle breeds from 10 American countries were assessed using 19 microsatellites. Heterozygosities, F-statistics estimates, genetic distances, multivariate analyses and assignment tests were performed. The levels of within-breed diversity detected in Creole cattle were considerable and higher than those previously reported for European breeds, but similar to those found in other Latin American breeds. Differences among breeds accounted for 8.4% of the total genetic variability. Most breeds clustered separately when the number of pre-defined populations was 21 (the most probable K value), with the exception of some closely related breeds that shared the same cluster and others that were admixed. Despite the high genetic diversity detected, significant inbreeding was also observed within some breeds, and heterozygote excess was detected in others. These results indicate that Creoles represent important reservoirs of cattle genetic diversity and that appropriate conservation measures should be implemented for these native breeds in order to minimize inbreeding and uncontrolled crossbreeding.

Polymicrogyria in standard poodles.

BACKGROUND: Polymicrogyria is a disorder of cerebrocortical migration resulting in increased numbers of small, disorganized gyri. This disorder occurs in Standard Poodles and in cattle. OBJECTIVES: To describe the clinical, electroencephalographic, imaging, and histopathologic features in poodles with polymicrogyria. ANIMALS: Five Standard Poodles with histologically confirmed polymicrogyria. METHODS: Retrospective case series. Cases were obtained by personal communication with 1 of 2 authors (TJVW, DPO). RESULTS: All dogs had cortical blindness and other neurologic abnormalities including gait and behavioral changes. Magnetic resonance imaging of 3 dogs showed multiple disorganized gyri, which were especially apparent on T2-weighted dorsal plane images. Electroencephalogram (EEG) of 1 dog revealed epileptiform discharges, including both spike and spike and wave discharges with voltage maximum potentials over the parietal/occipital region. The EEG supported that the repetitive behavior displayed by the dog was a complex partial motor seizure. One dog had concurrent hydrocephalus. All dogs had occipital lobe involvement and 2 dogs had involvement of other lobes. CLINICAL IMPORTANCE: The cases presented here demonstrate a larger age range (7 weeks to 5 years) and a decreased frequency of associated hydrocephalus when compared with the previous report.

Short-term administration of 17-beta estradiol to outbred male CD-1 mice induces changes in the immune system, but not in reproductive organs.

The magnitude of an immune response to many foreign and/or self-antigens is known to be gender-dependent and influenced by sex hormones. While the immune consequences of long-term exposure (3 to 5 months) to natural 17-beta estradiol in an inbred mouse model (e.g., C57BL/6, Balb/c) are relatively well-documented, the immunological effects of shorter-term 17-beta estradiol exposure in an outbred mouse model (CD-1) have not been thoroughly evaluated. The male outbred-CD-1 mouse is considered to be less 17-beta estradiol-responsive (in terms of reproductive changes) compared to the inbred mouse. In the present study, CD-1 male mice were dosed with vehicle, or 17-beta estradiol at 2 or 4 micrg/100 g body weight on alternate days over a 7-day period. The immune changes in the developmental organ (thymus) and mature lymphoid organ (spleen) were determined. Thymic organ weight/body weight ratio and thymocyte cellularity decreased with increasing dose of 17-beta estradiol, reaching significance at the 4 microg dose. Although 17-beta estradiol decreased thymocyte numbers, no differences were noted in the relative percentages of major thymocyte subsets (CD4+CD8-, CD4-CD8+, CD4+CD8+, CD4- CD8-) and no evidence of enhanced apoptosis was found. In contrast to the diminished thymocyte numbers, 17-beta estradiol increased splenic lymphocyte cellularity, especially in mice given 4 microg 17-beta estradiol dose. The functionality of splenocytes from mice exposed to 17-beta estradiol was also altered. Supernatants from Con-A activated splenocytes from 17-beta estradiol-treated mice had increased IFN-gamma and decreased IL-4 levels (p < 0.05 at the 4 microg dose). This increase in IFN-gamma in 17-beta estradiol-treated mice was not due to an increase in the relative percentages of T cells, since they were comparable to relative percentages of T cells from oil-treated control mice. In addition, supernatants from cultured splenocytes (both Con A-activated and unstimulated) also had significantly higher levels of nitric oxide activity, especially at the 4 microg 17-beta estradiol dose. These results indicate that short-term 17-beta estradiol treatment in outbred mice, at relatively modest doses (2-4 microg/100 g body weight), altered both thymocytes and splenocytes. These 17-beta estradiol-induced immune changes are compelling, since in these mice, post-17-beta estradiol exposure did not demonstrate robust changes in the male reproductive system (testicular and seminal vesical weights to body weight ratios).

Immunomodulation by diethylstilbestrol is dose and gender related: effects on thymocyte apoptosis and mitogen-induced proliferation.

It is believed, but not proven, that the immunomodulatory effects of DES may vary with the dose and/or gender. To address these critical gaps in the literature, diethylstilbestrol (DES) was administered to female and male CD-1 mice as four subcutaneous injections for 1 week at 0, 5, 15, and 30 microg/kg bw doses, and immunological and reproductive effects examined a day after the last injection. Female thymuses were significantly larger than their male counterparts. Short-term administration of DES to female or male mice neither induced thymic atrophy nor altered the relative percentages of thymic subsets. Nevertheless, DES treatment of female or male mice induced a dose-related apoptosis of CD4(+)8(+), CD4(+)8(-) and CD4(-)8(+) subsets as analyzed by 7-amino-actinomycin D (7-AAD). Immature CD4(-)8(-) subset of thymocytes from females was also affected by high dose DES. The pattern of mitogen-induced proliferation of splenic lymphocytes varied with the dose of hormone and the gender. In females, splenic lymphocytes from low dose DES (5 microg/kg bw)-treated mice exhibited an increased proliferative response to Con-A, LPS or PMA/ionomycin compared with controls. Similar cultures from mice treated with higher doses of DES (15 or 30 microg/kg bw) did not manifest an increased proliferative response, but rather showed a trend for suppressed proliferation, especially in response to Con-A. In males, DES had minimal effects with the exception of increased proliferative response to Con-A in splenocytes from medium-dose-DES-treated mice. The changes in mitogen-induced proliferation in DES-treated female mice were not mirrored by similar changes in the relative numbers of CD90(+) or CD45R(+) cells, or in ratios of anti-apoptotic Bcl-2 to apoptotic Bax proteins. Con-A-activated splenocytes from DES-treated mice, particularly from females, had a decreased ability to secrete interferon-gamma compared with controls. Taken together, these findings suggest that short-term exposure to DES has differential immunological effects depending upon the dose of hormone and sex.