Seven autochthonous Italian cattle breeds bred in the alpine area (Aosta Black Pied, Aosta Red Pied, Aosta Chestnut, Oropa Red Pied, Grey Alpine, Rendena and Burlina) were investigated in order to characterise their genetic structure and to study their phylogenetic origin. Two cattle breeds from Germany (Original German Brown and Holstein) and four from Switzerland (Simmental, Herens, Evolene and Brown Swiss) were included in the study in order to determine the genetic diversity existing among Italian local breeds, similar breeds bred on the other side of the Alps and in the well known Holstein. Seventeen microsatellites, of the internationally accepted panel for the study of cattle biodiversity, were used for the analysis. Microsatellites were highly polymorphic with a mean number of 5,5 alleles (ranging from 2 to 12 per locus). For each locus, allelic frequencies, heterozygosity (H) and the Polymorphism Information Content (PIC) were computed. The genetic equilibrium according to Hardy–Weinberg was calculated for each population and for each locus. Allele frequencies were used to estimate genetic distances and to draw a phylogenetic tree. The two closest breeds were Aosta Red Pied and Aosta Black Pied, while the two genetically most different were Holstein and Aosta Chestnut. Aosta valley breeds, Evolene and Herens constituted a tight cluster in the phylogenetic consensus tree. Principal component analysis showed a similar pattern for all the alpine breeds, while Holstein and Original German Brown were far away. The genetic differences among breeds were in accordance with their geographical and historical origins.
We estimated the genetic relationships between the endangered German Pustertaler-Sprinzen cattle breed and the Pinzgauer, Vosges and Simmental breeds--decided upon after consultation of the available historical literature. Within-breed diversity of the four breeds was also assessed. Twenty microsatellite markers were amplified in 27-50 unrelated individuals from populations of each breed. Within-breed variation was estimated from average heterozygosity values and mean number of alleles. Breed relationships were evaluated by genetic distance and a neighbour-joining tree was calculated from these estimates. Bootstrap resampling of loci tested the robustness of the tree topology obtained. A tree was also constructed from distance matrices using individual animals as operational taxonomic units. From both the average heterozygosity values and mean number of alleles calculated, the Pustertaler breed appears to be no more genetically impoverished than the other breeds analysed. The breed tree showed an 85% support for the Pustertaler-Pinzgauer grouping, and this result is echoed in the genetic distance values and allele-sharing individual tree.
Two methods have been developed for the assessment of conservation priorities on the basis of molecular markers. According to the Weitzman approach, contributions to genetic diversity are derived from genetic distances between populations. Alternatively, diversity within and across populations is optimized by minimizing marker-estimated kinships. We have applied, for the first time, both methods to a comprehensive data set of 69 European cattle breeds, including all cosmopolitan breeds and several local breeds, for which genotypes of 30 microsatellite markers in 25-50 animals per breed have been obtained. Both methods were used to calculate the gain in diversity if a breed was added to a set of nine non-endangered breeds. Weitzman-derived diversities were confounded by genetic drift in isolated populations, which dominates the genetic distances but does not necessarily increase the conservation value of a breed. Marker-estimated kinships across populations were less disturbed by genetic drift than the Weitzman diversities and assigned high conservation values to Mediterranean breeds, which indeed have genetic histories that differ from the non-endangered breeds. Prospects and limitations of marker-assisted decisions on conservation priorities are discussed.
A marker experiment with pigs from commercially selected lines is described. One important goal of the experiment was to map the porcine RN locus, a major gene responsible for lowered terminal pH and increased glycogen level in muscle tissue. Experimental families comprised 15 Piétrain × Hampshire boars, of which 14 were heterozygous at the RN locus, 61 homozygous rn(+) /rn(+) sows (five Landrace, 12 Large White, and 44 Landrace × Large White crossbreds), and 509 progenies, 496 of them from heterozygous boars, in total 585 animals. Genotyping was done for seven chromosome 15 microsatellite loci: Sw919, Sw964, S0088, Sw120, Sw906, Sw936, and Sw312. Genotype assignment for the RN locus was based on musculus longissimus dorsi glycogen content. The heterozygosity of markers ranged from 0.47 to 1 in boars and from 0.71 to 0.88 in sows. RN was mapped to the centre of an interval, flanked by Sw120 and the marker pair Sw906/Sw936. Male multipoint distances between RN and Sw120, Sw906, and Sw936 were estimated as 5 cM, 5 cM, and 6.9 cM, respectively. Two-point recombination rates between these markers and RN were 0.05 in all cases, with corresponding lod scores of 52.09, 29.30, and 42.53. Concordances and disconcordances of mapping results in the RN region from different studies are discussed. The male map length of the chromosome region covered was 68.8 cM, in contrast to the female map length of 124.7 cM. Significant differences in recombination rates between sexes were found in intervals Sw919-Sw964, Sw964-S0088, and Sw936-Sw312, but not in the neighbourhood of the RN gene. ZUSAMMENFASSUNG: Es wird ein Kartierungsexperiment mit Schweinen aus kommerziell genutzten Linien beschrieben. Vordringliches Ziel dieses Experimentes war es, das RN-Gen zu kartieren, das für einen erniedrigten End-pH-Wert und einen erhöhten Glykogengehalt im Musklegewebe verantwortlich ist. Die Daten stammen von 15 Hampshire × Piétrain Ebern, von denen 14 am RN Locus heterozygot waren, 61 homozygoten rn(+) /rn(+) Sauen (5 Landrasse-, 12 Large White und 44 Landrasse × Large White Kreuzungssauen) sowie 509 Nachkommen, 496 davon von heterozygoten Ebern, insgesamt also 585 Tiere. Für sieben Mikrosatellitenmarker auf Chromosom 15 wurden die Tiere typisiert: Sw919, Sw964, S0088, Sw120, Sw906 und Sw312. Die Bestimmung der Genotypen am RN-locus erfolgte anhand des Glykogenghalts im Musculus longissimus dorsi. Der Heterozygotiegrad der Marker lag zwischen 0, 47 und 1 bei Ebern und zwischen 0, 71 und 0, 88 bei den Sauen. Als Position des RN-Gens wurde die Mitte eines Intervalles bestimmt, der von dem Marker Sw120 sowie dem Markerpaar Sw906/Sw936 begrenzt wird. Für das männliche Geschlect wurden die Kartenabstände zwischen RN und Sw120, Sw906 und Sw936 in einer Mehrpunktanalyse auf 5 cM, 5 cM und 6, 9 cM geschätzt. Paarweise Schätzungen der Rekombinationsraten zwischen diesen Markern und RN betrugen in allen Fällen 0, 5, mit zugehörigen lod scores vol 52, 09, 29, 30 und 42, 53. übereinstimmungen und Diskrepanzen zwischen Kartierungsergebnissen verschiedener A...
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