Choice of shrinkage parameter and prediction of genomic breeding values in elite maize breeding populations     

Wenxin Liu  Tobias Würschum  Hans P. Maurer  Friedrich H. Longin  Nicolas Ranc  Hans P. Piepho  Jochen C. Reif 《Plant Breeding》2013,132(1):99-106

Genomic selection (GS) is a promising alternative to marker‐assisted selection particularly for quantitative traits. In this study, we examined the prediction accuracy of genomic breeding values by using ridge regression best linear unbiased prediction in combination with fivefold cross‐validation based on empirical data of a commercial maize breeding programme. The empirical data is composed of 930 testcross progenies derived from 11 segregating families evaluated at six environments for grain yield and grain moisture. Accuracy to predict genomic breeding values was affected by the choice of the shrinkage parameter λ², by unbalanced family size, by size of the training population and to a lower extent by the number of markers. Accuracy of genomic breeding values was high suggesting that the selection gain can be improved implementing GS in elite maize breeding programmes.  相似文献   

A Chick Embryo With a yet Unclassified Type of Cephalothoracopagus Malformation and a Hypothesis for Explaining its Genesis     

B. Maurer  S. H. Geyer  W. J. Weninger 《Anatomia, histologia, embryologia》2013,42(3):191-200

Cephalothoracopagus embryos are conjoined twins, who share parts of their heads, necks and bodies. Our study aims at presenting a detailed morphological analysis of a cephalothoracopagus chick embryo of developmental stage 31. Because none of the existing theories can explain the genesis of the phenotype of this embryo, we also suggest a hypothesis, which explains it. Beside the cephalothoracopagus embryo, we investigated five control embryos. With the aid of the high‐resolution episcopic microscopy (HREM) technique, we created digital volume data and three‐dimensional (3D) computer models of the organs and arteries of the embryos. We used the 3D models for topological analysis and for measuring the diameters of the great intrathoracic arteries. The malformed embryo showed two body backs, each containing a notochord, spinal cord and dorsal aorta. The body backs continued into separated lower bodies. The embryo had a single, four‐chambered heart, single respiratory tract and single upper alimentary tract. The topology of the pharyngeal arch arteries was normal, and the diameters of these arteries were similar to that of the control embryos. We classified the embryo we investigated as a yet unknown malformation and suggest a hypothesis explaining its genesis.  相似文献   

Extent of utilisation of dual‐purpose wheat for grazing by late‐pregnant and lambing ewes and producer‐reported incidence of health issues in southern New South Wales     

SR McGrath  JJ Lievaart  MA Friend 《Australian veterinary journal》2013,91(10):432-436

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Incidence of calf scours and associated risk factors in southern New South Wales beef herds     

JJ Lievaart  NR Charman  C Scrivener  A Morton  MB Allworth 《Australian veterinary journal》2013,91(11):464-468

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Mucopolysaccharidosis type VI in a Miniature Poodle-type dog caused by a deletion in the arylsulphatase B gene     

RD Jolly  JJ Hopwood  NR Marshall  KS Jenkins  DJ Thompson  KE Dittmer 《New Zealand veterinary journal》2013,61(3):183-188

Abstract

AIM: To investigate and characterise an inborn error of metabolism in a dog with skeletal and ocular abnormalities.

METHODS: A 2.5-year-old small male Miniature Poodle-like dog was presented with gross joint laxity and bilateral corneal opacities. Clinical examination was augmented by routine haematology, serum chemistry, radiographs, pathology, enzymology and molecular genetic studies. Euthanasia was requested when the dog was 3 years of age because of progressively decreasing quality of life.

RESULTS: Radiology revealed generalised epiphyseal dysplasia, malformed vertebral bodies, luxation/subluxation of appendicular and lumbosacral joints with hypoplasia of the odontoid process and hyoid apparatus. These clinical and radiographic findings, together with a positive urinary Berry spot test for mucopolysaccharides, and metachromatic granules in leucocytes, were indicative of a mucopolysaccharidosis (MPS), a lysosomal storage disease. Histological lesions included vacuolation of stromal cells of the cornea, fibroblasts, chondrocytes, macrophages and renal cells. The brain was essentially normal except for moderate secondary Wallerian-type degeneration in motor and sensory tracts of the hind brain. Dermatan sulphate-uria was present and enzymology revealed negligible activity of N-acetylgalactosamine-4-sulphatase, also known as arylsulphatase B, in cultured fibroblasts and liver tissue. A novel homozygous 22 base pair (bp) deletion in exon 1 of this enzyme's gene was identified (c.103_124del), which caused aframe-shift and subsequent premature stop codon. The “Wisdom pure breed-mixed breed” test reported the dog as a cross between a Miniature and Toy Poodle.

CONCLUSIONS: The clinicopathological features are similar to those of MPS type VI as previously described in dogs, cats and other species, and this clinical diagnosis was confirmed by enzymology and molecular genetic studies. This is an autosomal recessively inherited lysosomal storage disease.

CLINICAL RELEVANCE: The prevalence of MPS VI in Miniature or Toy Poodles in New Zealand and elsewhere is currently unknown. Due to the congenital nature of the disorder, malformed pups may be subject to euthanasia without investigation and the potential genetic problem in the breed may not be fully recognised. The establishment of a molecular genetic test now permits screening for this mutation as a basis to an informed breeding policy.  相似文献   

Estriolum Treatment in the Bitch: A Risk for Uterine Infection?     

BA Schotanus  J de Gier  JJ van der Lugt  AC Okkens 《Reproduction in domestic animals》2008,43(2):176-180

Purulent vaginal discharge in a bitch in which ovariohysterectomy has been performed is often caused by inflammation of the uterine stump. The inflammation is due to either cystic endometrial hyperplasia (CEH) induced primarily by progesterone from remnant ovarian tissue or exogenous progestagens, or it is due to the presence of unabsorbed suture material. This report describes a 9-year-old Irish setter with hemopurulent vaginal discharge and non-pruritic symmetrical alopecia, which had undergone ovariohysterectomy 3.5 years ago and which had been treated with estriolum daily for the past 2.5 years because of urinary incontinence. Vaginoscopy revealed hemopurulent discharge throughout the vagina and vestibule. Cytological examination of ultrasound-guided fine-needle aspiration biopsies of a large mass in the hypogastricum, which appeared to be the uterine cervical stump, revealed septic purulent inflammation. The concentration of plasma progesterone was low and the concentration of plasma 17-ß oestradiol did not increase after gonadotrophin-releasing hormone administration. No remnant ovarian tissue was found by abdominal ultrasonography, laparotomy, or histological examination of mesovarian pedicles. Laparotomy revealed uterine stump empyema. Histological examination of the surgically removed mass excluded both CEH and unabsorbed suture material as the cause of the stump empyema. Instead, it is hypothesized that the long-term treatment with estriolum was a causative factor. This suggests that bitches treated with estriolum should be examined regularly.  相似文献   

Dangling bond dynamics on the silicon (100)-2x1 surface: dissociation, diffusion, and recombination     

M McEllistrem  M Allgeier  JJ Boland 《Science (New York, N.Y.)》1998,279(5350):545-548

The dynamics of dangling bond (DB) diffusion was studied after deuterium desorption from the silicon (100)-2x1 surface. At elevated temperatures, paired DB sites produced after desorption unpaired as deuterium atoms hopped from adjacent dimers. Below 620 kelvin, the unpaired configuration most commonly observed corresponded to two DBs on adjacent silicon dimers. At higher temperatures, unpaired DBs executed one-dimensional walks along the dimer rows, and recombination was observed with the same partner after walks lasting many minutes. The frequency and extent of these excursions increased with temperature. Above 660 kelvin, complete dissociation was observed and was sometimes followed by recombination by means of partner exchange. The implications for low-temperature materials growth are discussed.  相似文献   

Direct observations of structural phase transitions in planar crystallized ion plasmas     

TB Mitchell  JJ Bollinger  DHE Dubin  X Huang  WM Itano  RH Baughman 《Science (New York, N.Y.)》1998,282(5392):1290-1293

Laser-cooled 9Be+ ions confined in two-dimensionally extended lattice planes were directly observed, and the images were used to characterize the structural phases of the ions. Five different stable crystalline phases were observed, and the energetically favored structure could be sensitively tuned by changing the areal density of the confined ions. The experimental results are in good agreement with theoretical predictions for the planar (infinite in two dimensions) one-component plasma. Qualitatively similar structural phase transitions occur, or are predicted to occur, in other experimentally realizable planar systems.  相似文献   

Thermodynamics of calcite growth: baseline for understanding biomineral formation     

HH Teng  PM Dove  CA Orme  De Yoreo JJ 《Science (New York, N.Y.)》1998,282(5389):724-727

The complexity of biomineralized structures suggests the potential of organic constituents for controlling energetic factors during crystal synthesis. Atomic force microscopy was used to investigate the thermodynamic controls on carbonate growth and to measure the dependence of step speed on step length and the dependence of critical step length on supersaturation in precisely controlled solutions. These data were used to test the classic Gibbs-Thomson relationship and provided the step edge free energies and free energy barriers to one-dimension nucleation for calcite. Addition of aspartic acid, a common component in biomineralizing systems, dramatically affected growth morphology and altered the magnitude of the surface energy.  相似文献   

Rice with fish culture in the semi-deep waters of the Mekong Delta, Vietnam: a socio-economical survey   总被引：1，自引：0，他引：1  

A J Rothuis  D K Nhan  C JJ Richter  F Ollevier 《Aquaculture Research》1998,29(1):47-57

The results of a socio-economical survey of farming systems practising rice culture with introduced fish, rice culture with indigenous fish and rice monoculture in the semi-deep waters of the Mekong Delta, Vietnam, are presented. Rice and fish yields, inputs, and cost-benefits were computed to evaluate the agricultural effects of rice with fish culture. Household size, labour availability and educational level were not significantly different among the three farming systems. Rice-fish farming systems differed mainly from rice monoculture by a higher fertilizer/ water requirement and less pesticide use. The total farm cash and net return did not differ among the farming systems. The main beneficial effects of rice-fish culture are thought to be related to environmental sustainability, system biodiversity, farm diversification and household nutrition.  相似文献