Patterns of homozygosity in insular and continental goat breeds

Background: Genetic isolation of breeds may result in a significant loss of diversity and have consequences on health and performance. In this study, we examined the effect of geographic isolation on caprine genetic diversity patterns by genotyping 480 individuals from 25 European and African breeds with the Goat SNP50 BeadChip and comparing patterns of homozygosity of insular and nearby continental breeds. Results: Among the breeds analysed, number and total length of ROH varied considerably and depending on breeds, ROH could cover a substantial fraction of the genome (up to 1.6 Gb in Icelandic goats). When compared with their continental counterparts, goats from Iceland, Madagascar, La Palma and Ireland (Bilberry and Arran) displayed a significant increase in ROH coverage, ROH number and F ROH values (P value < 0.05). Goats from Mediterranean islands represent a more complex case because certain populations displayed a significantly increased level of homozygosity (e.g. Girgentana) and others did not (e.g. Corse and Sarda). Correlations of number and total length of ROH for insular goat populations with the distance between islands and the nearest continental locations revealed an effect of extremely long distances on the patterns of homozygosity. Conclusions: These results indicate that the effects of insularization on the patterns of homozygosity are variable. Goats raised in Madagascar, Iceland, Ireland (Bilberry and Arran) and La Palma, show high levels of homozygosity, whereas those bred in Mediterranean islands display patterns of homozygosity that are similar to those found in continental populations. These results indicate that the diversity of insular goat populations is modulated by multiple factors such as geographic distribution, population size, demographic history, trading and breed management

Microsatellite diversity of the Nordic type of goats in relation to breed conservation: how relevant is pure ancestry?

In the last decades, several endangered breeds of livestock species have been re-established effectively. However, the successful revival of the Dutch and Danish Landrace goats involved crossing with exotic breeds and the ancestry of the current populations is therefore not clear. We have generated genotypes for 27 FAO-recommended microsatellites of these landraces and three phenotypically similar Nordic-type landraces and compared these breeds with central European, Mediterranean and south-west Asian goats. We found decreasing levels of genetic diversity with increasing distance from the south-west Asian domestication site with a south-east-to-north-west cline that is clearly steeper than the Mediterranean east-to-west cline. In terms of genetic diversity, the Dutch Landrace comes next to the isolated Icelandic breed, which has an extremely low diversity. The Norwegian coastal goat and the Finnish and Icelandic landraces are clearly related. It appears that by a combination of mixed origin and a population bottleneck, the Dutch and Danish Land-races are separated from the other breeds. However, the current Dutch and Danish populations with the multicoloured and long-horned appearance effectively substitute for the original breed, illustrating that for conservation of cultural heritage, the phenotype of a breed is more relevant than pure ancestry and the genetic diversity of the original breed. More in general, we propose that for conservation, the retention of genetic diversity of an original breed and of the visual phenotype by which the breed is recognized and defined needs to be considered separately

Polizeialltag und Habitus: Eine sozialökologische Fallstudie

Hüttermann J. Polizeialltag und Habitus: Eine sozialökologische Fallstudie. Soziale Welt. 2000;51:7-24

The Microphthalmia-Associated Transcription Factor Mitf Interacts with β-Catenin To Determine Target Gene Expression

Commitment to the melanocyte lineage is characterized by the onset of expression of the microphthalmia-associated transcription factor (Mitf). This transcription factor plays a fundamental role in melanocyte development and maintenance and seems to be crucial for the survival of malignant melanocytes. Furthermore, Mitf has been shown to be involved in cell cycle regulation and to play important functions in self-renewal and maintenance of melanocyte stem cells. Although little is known about how Mitf regulates these various processes, one possibility is that Mitf interacts with other regulators. Here we show that Mitf can interact directly with β-catenin, the key mediator of the canonical Wnt signaling pathway. The Wnt signaling pathway plays a critical role in melanocyte development and is intimately involved in triggering melanocyte stem cell proliferation. Significantly, constitutive activation of this pathway is a feature of a number of cancers including malignant melanoma. Here we show that Mitf can redirect β-catenin transcriptional activity away from canonical Wnt signaling-regulated genes toward Mitf-specific target promoters to activate transcription. Thus, by a feedback mechanism, Mitf can diversify the output of canonical Wnt signaling to enhance the repertoire of genes regulated by β-catenin. Our results reveal a novel mechanism by which Wnt signaling and β-catenin activate gene expression, with significant implications for our understanding of both melanocyte development and melanoma

Genomic, transcriptional and mutational analysis of the mouse microphthalmia locus [In Process Citation]

Mouse microphthalmia transcription factor (Mitf) mutations affect the development of four cell types: melanocytes, mast cells, osteoclasts, and pigmented epithelial cells of the eye. The mutations are phenotypically diverse and can be arranged in an allelic series. In humans, MITF mutations cause Waardenburg syndrome type 2A (WS2A) and Tietz syndrome, autosomal dominant disorders resulting in deafness and hypopigmentation. Mitf mice thus represent an important model system for the study of human disease. Here we report the complete exon/intron structure of the mouse Mitf gene and show it to be similar to the human gene. We also found that the mouse gene is transcriptionally complex and is capable of generating at least 13 different Mitf isoforms. Some of these isoforms are missing important functional domains of the protein, suggesting that they might play an inhibitory role in Mitf function and signal transduction. In addition, we determined the molecular basis for six microphthalmia mutations. Two of the mutations are reported for the first time here (Mitf(mi-enu198) and Mitf(mi-x39)), while the others (Mitf(mi-ws), Mitf(mi-bws), Mitf(mi-ew), and Mitf(mi-di)) have been described but the molecular basis for the mutation not determined. When analyzed in terms of the genomic and transcriptional data presented here, it is apparent that these mutations result from RNA processing or transcriptional defects. Interestingly, three of the mutations (Mitf(mi-x39), Mitf(mi-bws), and Mitf(mi-ws)) produce proteins that are missing important functional domains of the protein identified in in vitro studies, further confirming a biological role for these domains in the whole animal

At the world’s edge: reconstructing diet and geographic origins in medieval Iceland using isotope and trace element analyses

Objectives. A multi-isotope study was conducted on individuals buried at Skriðuklaustur monastery (AD 1493–1554) to investigate their geographic origins and dietary composition. Comparative material from individuals excavated from Skeljastaðir, an inland farm site was also analysed. Materials and Methods. Bone collagen was extracted from 50 humans (Skriðuklaustur and Skeljastaðir) and 25 animals (Skriðuklaustur) and analysed for δ13C, δ15N and δ34S. Dental enamel samples from 31 individuals (Skriðuklaustur) were also analysed for 87Sr/86Sr, δ18O, δ13C and trace elements (Pb, Sr, Zn, Ba). Results. The mean value determined from individuals from Skriðuklaustur (n = 36) was δ13C = –18.7 ± 0.8 ‰, δ15N = 12.8 ± 1.1 ‰ and δ34S = 9.0 ± 1.6 ‰, whereas at Skeljastaðir (n = 14) it was δ13C = –20.5 ± 0.8 ‰, δ15N = 7.8 ± 0.9‰ and δ34S = 9.4 ± 1.6‰. At Skriðuklaustur, human dental enamel samples (n = 31) provided a 87Sr/86Sr range of 0.7060–0.7088, δ18Ophosphate from 13.9 ‰ to 16.1 ‰ and δ13Ccarbonate from –16.6 ‰ to –12.9 ‰. Inferred drinking water (δ18Odw) values range from –12.3 ‰ to –8.9 ‰. Sr concentrations range from 25.8 to 156.7 ppm, Ba from 0.11 to 0.81 ppm, Zn from 43.8 to 145.8 ppm and Pb from 0.13 to 9.40 ppm. Discussion. A combination of results indicate that the people from Skriðuklaustur were born in Iceland, but some lived inland during childhood while some lived closer to the coast. Since Skriðuklaustur was a hospital, these individuals may have sought medical treatment at the monastery. The δ13C and δ15N values determined from bone collagen indicate that the people residing at Skriðuklaustur consumed a diet high in marine protein, while those residing at Skeljastaðir exhibit values more consistent with terrestrial resources