The Fe2(+)-Mg interdiffusion in orthopyroxene: Constraints from cation ordering and structural data and implications for cooling rates of meteorites

Orthopyroxene crystals in a number of meteorites exhibit compositional zoning of Fe and Mg, which provide important constraint on their cooling rates. However, attempts to model cooling rate of these crystals from Fe-Mg zoning profiles suffer from the lack of any measured or theoretically well constrained Fe-Mg interdiffusion data in OP(x) It has been assumed that Fe-Mg interdiffusion in OP(x) only slightly slower than that in olivine. The purpose of this paper is to (1) calculate the Fe-Mg fractionation, and (2) provide analytical formulation relating cooling rate to the length of the diffusion zone across the interface of the overgrowth of a mineral on itself with application to Mg diffusion profile across OP(x) growth on OP(x) in certain mesosiderites

Identification of mutations in the bovine KIT gene, a candidate for the Spotted locus in cattle

AbstractIn mammals, abnormal migration of melanoblasts from the neural crest during embryonic development may be the reason of the pielbaldism phenotype that is a mixture of pigmented and unpigmented areas in the coat. Several cattle breeds, like for example Holstein, show the piebald spotted coat colour phenotype, that, according to crossbreeding studies, is due to a recessive allele (s), member of the allele series of the Spotted (S) locus. Dominant alleles at this locus act as suppressors of the spotted pattern and produce uniformly pigmented animals while others determine the colour-sided pattern known, for example, in the Hereford breed. The bovine v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene (KIT) gene was localized in the region of chromosome 6 where the Spotted locus was mapped. KIT plays a major role during the embryonic development in directing the migration of the melanoblasts from the neural crest. Mutations in this gene cause different coat colour patterns in mouse and human. In pigs..

Analysis of melanocortin 1 receptor (MC1R) gene polymorphisms in some cattle breeds: their usefulness and application for breed traceability and authentication of Parmigiano Reggiano cheese

l legame tra un prodotto di origine animale e la razza da cui questo \ue8 originato rappresenta un aspetto importante per la valorizzazione di alcune produzioni. Il maggior prezzo che questi prodotti spuntano sul mercato fa emergere l\u2019esigenza di poter autenticare o tracciare i prodotti mono-razza per smascherare e scoraggiare possibili frodi. A questo scopo sono stati proposti sistemi di analisi del DNA, alcuni dei quali utilizzano marcatori in geni che determinano il colore del mantello, che \ue8 uno dei principali caratteri che differenziano tra di loro le razze. Diverse mutazioni nel gene melanocortin 1 receptor (MC1R) sono gi\ue0 state associate a particolari effetti sul colore del mantello nella specie bovina. In questa ricerca abbiamo studiato la presenza dei principali alleli al locus MC1R, per valutare la possibilit\ue0 di utilizzare questo gene per l\u2019autenticazione e la tracciabilit\ue0 di razza dei prodotti lattiero-caseari. Le mutazioni che permettono di distinguere questi alleli sono state analizzate utilizzando protocolli di PCR-RFLP e PCR-APLP su un totale di 1360 animali appartenenti a 18 razze bovine. Per ognuna delle seguenti razze, Frisona Italiana, Bruna Italiana, Pezzata Rossa Italiana, Jersey, Rendena, Reggiana e Modenese, \ue8 stato possibile analizzare pi\uf9 di 70 animali. L\u2019allele Ed \ue8 stato identificato nella razza Frisona Italiana con una frequenza dello 0,886. L\u2019allele E (nomenclatura che include tutti gli alleli tranne che e, Ed e E1) \ue8 stato identificato con alta frequenza nella Bruna Italiana (0,591), Rendena (0,738), Jersey (0,955) e Modenese (0,961) e con bassa frequenza nella Pezzata Rossa Italiana (0,029). Inoltre, questo allele \ue8 stato osservato nella Rossa Svedese, Rossa Danese, Grigio Alpina, Piemontese, Romagnola, Marchigiana e Chianina. In alcune di queste razze (Bruna Italiana, Rendena, Grigio Alpina, Piemontese, Rossa Svedese e Rossa Danese) \ue8 stato identificato anche l\u2019allele E1. L\u2019allele e \ue8 risultato fissato nella razza Reggiana e quasi fissato nella razza Pezzata Rossa Italiana. Inoltre, con bassa frequenza, \ue8 stato identificato in tutte le altre razze analizzate, tranne che nella Marchigiana. Le differenze osservate tra razze esaminate indicano che, almeno in alcuni casi, \ue8 possibile utilizzare i polimorfismi del gene MC1R per escludere o confermare l\u2019impiego di latte di una determinata razza nella produzione di un prodotto lattiero-caseario. Il caso pi\uf9 interessante \ue8 quello del formaggio Parmigiano Reggiano prodotto con l\u2019uso esclusivo di latte di bovine di razza Reggiana. Infatti, essendo presente in questa razza soltanto l\u2019allele e il rilievo analitico di qualsiasi altro allele nel DNA estratto dal formaggio rivela l\u2019uso di latte proveniente da altre razze. La messa a punto di un metodo PCR-RFLP per l\u2019analisi del DNA estratto da prodotti lattiero caseari, incluso il Parmigiano Reggiano di oltre 24 mesi di stagionatura, rappresenta uno strumento importante per la difesa di questo prodotto mono-razza da eventuali frodi. I risultati ottenuti su 10 forme di formaggio prodotto esclusivamente con latte di bovine di razza Reggiana e su 15 forme di Parmigiano Reggiano commerciale ottenuto senza restrizione della razza di origine del latte hanno mostrato la validit\ue0 del metodo del quale \ue8 stata valutata anche la sensibilit\ue0n cattle, the MC1R gene has been the subject of several studies with the aim to elucidate the biology of coat colour. Then, polymorphisms of this gene have been proposed as tools for breed identification and animal products authentication. As a first step to identify breed specific DNA markers that can be used for the traceability of mono-breed dairy cattle products we investigated, using PCR-RFLP and PCR-APLP protocols, the presence and distribution of some alleles at the MC1R locus in 18 cattle breeds for a total of 1360 animals. For each of seven breeds (Italian Holstein, Italian Brown, Italian Simmental, Rendena, Jersey, Reggiana and Modenese) a large number of animals (>70) was genotyped so the obtained results can be considered with more confidence. Allele Ed was identified only in black pied cattle (Italian Holstein and Black Pied Valdostana). Allele E (this nomenclature includes all alleles except Ed, E1 and e) was observed in Italian Brown, Rendena, Jersey, Modenese, Italian Simmental, Grigio Alpina, Piedmontese, Chianina, Romagnola, Marchigiana, Swedish Red and White and Danish Red. Allele E1 was identified in Italian Brown, Rendena, Grigio Alpina, Piedmontese, Swedish Red and White and Danish Red. The recessive allele e, known to cause red coat colour, was fixed in Reggiana and almost fixed in Italian Simmental. This allele was observed also in Italian Holstein, Italian Brown, Rendena, Jersey and Modenese albeit with low frequency. Moreover, this allele was detected in Valdostana, Pezzata Rossa d\u2019Oropa, Piedmontese, Romagnola, Swedish Red and White, Danish Red, Charoleis and Salers. In the case of the Reggiana breed, which is fixed for allele e, the MC1R locus is highly informative with respect to breeds that carry other alleles or in which allele e is at very low frequency. In theory, using the MC1R locus it is possible to identify the presence of milk from some other breeds in Parmigiano Reggiano cheese labelled as exclusively from the Reggiana breed. This possibility was practically tested by setting up protocols to extract and analyse polymorphisms of the MC1R locus in several dairy products, including Parmigiano Reggiano cheese cured for 30 months. The lower detection limit was estimated to be 5% of non expected DNA. This test can represent a first deterrent against fraud and an important tool for the valorisation and authentication of Parmigiano Reggiano cheese obtained from only Reggiana milk

investigation of the agouti gene for the identification of useful markers for coat colour association studies in domestic rabbits

AbstractIn wild-type mice, it is well known that Agouti is expressed in skin where it controls the banded-hair Agouti phenotype. Molecular genetics and pharmacological studies show that mutually exclusive binding of the melanocortin 1 receptor (MC1R) by the Agouti protein or by -melanocyte-stimulating hormone (a-MSH) signals hair-bulb melanocytes to synthesise preferentially either pheomelanin (yellow-red pigment) or eumelanin (black-brown pigment), respectively. In mice as well as in other species, loss-of-function mutations of the Agouti gene determine only the production of eumelanin while gain-of-function mutations lead to pheomelanin production. A variety of coat colours appear as a result of these alterations that show also epistatic interactions with MC1R mutations. In rabbit, classical studies have suggested the presence of three alleles at the Agouti locus: A (wild type allele), at (black and tan) and a (non-agouti). We recently showed that mutations in the rabbit MC1R gene are associated with c..

Non-invasive and simple methods for sampling rabbit DNA for PCR analysis of melanocortin 1 receptor (MC1R) gene mutations: a technical note

[EN] Simple and non-invasive methods of collecting and preserving biological specimens for genetic analysis can be useful in reducing the discomfort of the involved animals and can be applicable for highthroughput studies that require a large number of biosamples. In order to have the possibility to analyse a large number of samples and making easier the collection of rabbit biological materials as well as to reduce the cost and time of the genotyping procedures, here we tested different protocols for the genotyping of mutations identified in the rabbit melanocortin receptor 1 (MC1R) gene that are associated to coat colours in different rabbit breeds. These protocols make use of rabbit hair roots or cell preparations from buccal swabs with a direct PCR amplification without previous DNA extraction. Hair samples were collected from 60 rabbits of different breeds and preserved for up to 12 months at 4°C. For each hair sample 5-10 hair roots were clipped a few mm from the root directly within a 0.2 ml PCR tube. Buccal cells were collected from 10 crossbred and purebred rabbits and prepared after a few steps for PCR. The PCR fragments were analysed by means of polyacrylamide gel electrophoresis and stained with ethidium bromide or using fluorescent labelled products resolved in a capillary automatic sequencer. The success genotyping rate of the hair and buccal cell samples was 98% and 80%, respectively. These values are comparable to the success rates of other protocols described in human or other animals involving previous DNA extraction. The obtained results show that noninvasive methods of biological specimen collection that make it possible to analyse the DNA without previous extraction can be easily and routinely applied in rabbit molecular genetic studies. However, due to the higher success rate and the easier method of collection, plucked hairs seem the best source for high-throughput biosampling in this species.This work was supported by RFO funds from the University of Bologna. We thank several rabbit breeders and Associazione Nazionale Coniglicoltori Italiani (ANCI) for their collaboration in the sampling of biological materialsFontanesi, L.; Tazzoli, M.; Russo, V. (2007). Non-invasive and simple methods for sampling rabbit DNA for PCR analysis of melanocortin 1 receptor (MC1R) gene mutations: a technical note. World Rabbit Science. 15(2). https://doi.org/10.4995/wrs.2007.598SWORD15