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Fatty acid composition of goat muscles and fat depots: a review.

In addition to the fat content of muscle and adipose depots, the fatty acid composition of lipids affects meat quality. Furthermore, relevant reports are difficult to use for comparisons, in that samples were collected from muscles and fat depots at various anatomical locations and experiments entailed different objectives, designs, procedures and methodologies. Nonetheless, based on currently available publications, according to a recent classification of meats by concentrations of potentially cholesterol-raising, and neutral, and cholesterol-lowering effects, average values for goat muscles appear better than for beef and lamb. Feeding dry diets seems to increase levels of unsaturated fatty acids and stearic acid in fat depots compared with milk or milk replacer. Increasing concentrate consumption can increase levels of odd-numbered and branched chain fatty acids in subcutaneous fat depots. With increasing age of unweaned kids, the level of stearic acid in fat depots decreases, and with increasing live weight of weaned kids levels of saturated fatty acids increase, and contents of monounsaturated fatty acids decrease in most fat depots. This review of a currently limited database indicates need for further experimentation to characterize interactions among factors such as breed, age and nutritional conditions in the fatty acid composition of carcass lipids of goats so as to gain a fuller understanding of goat meat quality.

Journal Article↗

Determination of volatile compounds in cows' milk using headspace GC-MS.

The composition of the volatile fraction of milk from cows was investigated in a survey of milk samples using a headspace sampling technique and gas chromatography coupled to mass spectrometry analysis (GC-MS). Milk samples were collected from 12 farms, selected for similar management, breed and level of production. Farms were also grouped according to the type of forage in the ration: (1) hay; (2) hay and maize silage; (3) hay, maize silage and grass silages. Forty-one compounds in milk were isolated and identified from GC-MS headspace analysis. Quantitatively, the most representative chemical class was ketones (eight compounds, 170 microg/kg), followed by aldehydes (nine compounds, 63 microg/kg), alcohols (eight compounds, 36 microg/kg), and lower amounts of hydrocarbons (six compounds), sulphur compounds (three compounds), esters (four compounds) and terpenes (three compounds). The novel headspace sampling technique, and the consequent reduction of sample pre-treatment, allowed the identification of low-molecular weight volatile compounds, and reduced the risk of producing artefacts during analysis. Discriminant analysis was used to identify a classification criterion for milk samples, using type of forage in the ration as a grouping variable. Posterior probability error rate indicated that aldehydes provided one of the best discriminant criteria for grouping milks according to ration composition. When all 41 identified volatile compounds were included, discriminant analysis selected nine compounds (acetone, 2,3-butanedione, 2-butanone, ethanol, acetaldehyde, ethylacetate, ethvlisovalerate, dimethylsulphone) that did not fail the tolerance test and which correctly classified 100% of the original cases.

Alcohols↗

Dryadomyces amasae: a nutritional fungus associated with ambrosia beetles of the genus Amasa (Coleoptera: Curculionidae, Scolytinae).

During surveys of woodlands in Taiwan a previously undescribed fungus Dryadomyces amasae gen. sp. nov., was found in the sapwood of dead angiosperm timbers in the gallery systems of the scolytine ambrosia beetle Amasa concitatus. The fungus grows predominantly in the immediate vicinity of the feeding beetle larvae and serves as a nutritional ambrosia fungus. The transmission of D. amasae to new breeding substrates is ensured by an oral mycetangium, a paired organ which was found in A. concitatus and A. aff. glaber near the mandibles and contained multiple cells of the fungus. Morphologically D. amasae resembles species of Ambrosiella. However, phylogenetic analysis based on partial nucSSU rDNA placed the fungus with certain species of the genus Ambrosiella within the Ophiostomatales, whereas the type species of Ambrosiella, A. xylebori, was assigned to the Microascales. A. xylebori, as well as A. ferruginea and A. hartigii, demonstrated phialidic conidial development, leading to an emendation of the description of the genus Ambrosiella. In contrast, Dryadomyces exhibited conidial development by apical, sympodial wall formation with prominent denticles bearing conidia. Other, previously described Ambrosiella species exhibited non-phialidic conidiogenesis, but lacked denticles on the conidiophores. Consequently, their classification needs further revision.

Ambrosia↗

Genetic markers applied in regression tree prediction models.

Classification and regression tree (CART) modelling was used to determine infectious hypodermal and haematopoietic necrosis virus (IHHNV) resistance and susceptibility in Penaeus stylirostris. In a previous study, eight random amplified polymorphic DNA (RAPD) markers and viral load values using real-time quantitative PCR were obtained and used as the training data set in order to create numerous regression tree models. Specifically, the genetic markers were used as categorical predictor variables and viral load values as the dependent response variable. To determine which model has the highest predictive accuracy for future samples, RAPD fingerprint data was generated from new Penaues stylirostris IHHNV resistant and susceptible individuals and used to test the regression models. The best performing tree was a four terminal node tree with three genetic markers as significant variables. Marker-assisted breeding practices may benefit from the creation of regression tree models that apply genetic markers as predictive factors. To our knowledge this is the first study to use RAPD markers as predictors within a CART prediction model to determine viral susceptibility.

Animals↗

A horse of a different colour: do patients with semantic dementia recognise different versions of the same object as the same?

Ten patients with semantic dementia resulting from bilateral anterior temporal lobe atrophy, and 10 matched controls, were tested on an object recognition task in which they were invited to choose (from a four-item array) the picture representing "the same thing" as an object picture that they had just inspected and attempted to name. The target in the response array was never physically identical to the studied picture but differed from it - in the various conditions - in size, angle of view, colour or exemplar (e.g. a different breed of dog). In one test block for each patient, the response array was presented immediately after the studied picture was removed; in another block, a 2 min filled delay was inserted between study and test. The patients performed relatively well when the studied object and target response differed only in the size of the picture on the page, but were significantly impaired as a group in the other three type-of-change conditions, even with no delay between study and test. The five patients whose structural brain imaging revealed major right-temporal atrophy were more impaired overall, and also more affected by the 2 min delay, than the five patients with an asymmetric pattern characterised by predominant left-sided atrophy. These results are interpreted in terms of a hypothesis that successful classification of an object token as an object type is not a pre-semantic ability but rather results from interaction of perceptual and conceptual processing.

Adult↗

Development of ESTs from chickpea roots and their use in diversity analysis of the Cicer genus.

BACKGROUND: Chickpea is a major crop in many drier regions of the world where it is an important protein-rich food and an increasingly valuable traded commodity. The wild annual Cicer species are known to possess unique sources of resistance to pests and diseases, and tolerance to environmental stresses. However, there has been limited utilization of these wild species by chickpea breeding programs due to interspecific crossing barriers and deleterious linkage drag. Molecular genetic diversity analysis may help predict which accessions are most likely to produce fertile progeny when crossed with chickpea cultivars. While, trait-markers may provide an effective tool for breaking linkage drag. Although SSR markers are the assay of choice for marker-assisted selection of specific traits in conventional breeding populations, they may not provide reliable estimates of interspecific diversity, and may lose selective power in backcross programs based on interspecific introgressions. Thus, we have pursued the development of gene-based markers to resolve these problems and to provide candidate gene markers for QTL mapping of important agronomic traits. RESULTS: An EST library was constructed after subtractive suppressive hybridization (SSH) of root tissue from two very closely related chickpea genotypes (Cicer arietinum). A total of 106 EST-based markers were designed from 477 sequences with functional annotations and these were tested on C. arietinum. Forty-four EST markers were polymorphic when screened across nine Cicer species (including the cultigen). Parsimony and PCoA analysis of the resultant EST-marker dataset indicated that most accessions cluster in accordance with the previously defined classification of primary (C. arietinum, C. echinospermum and C. reticulatum), secondary (C. pinnatifidum, C. bijugum and C. judaicum), and tertiary (C. yamashitae, C. chrossanicum and C. cuneatum) gene-pools. A large proportion of EST alleles (45%) were only present in one or two of the accessions tested whilst the others were represented in up to twelve of the accessions tested. CONCLUSION: Gene-based markers have proven to be effective tools for diversity analysis in Cicer and EST diversity analysis may be useful in identifying promising candidates for interspecific hybridization programs. The EST markers generated in this study have detected high levels of polymorphism amongst both common and rare alleles. This suggests that they would be useful for allele-mining of germplasm collections for identification of candidate accessions in the search for new sources of resistance to pests / diseases, and tolerance to abiotic stresses.

Biomarkers↗

[Studies of necrotizing enteritis of suckling piglets (Clostridium perfringens type C enterotoxemia) in industrialized sow breeding units. 4. Epizootiology].

Necrotising enteritis had been the cause of death of 4.9 per cent in 5,177 nursed piglets, which was established by pathological examination. The number of piglets, in that context, which had come from industrialised sow breeding units was equivalent to 92 per cent. The nursed piglet held the third position, next to smaller ruminants (19.4 per cent) and fowl (6.0 per cent), with regard to the occurrence of Clostridium perfringens enterotoxemia or necrotising enteritis in 112,218 animals which were pathologically examined after death. Necrotising enteritis so far has been rare in the GDR. No regional accumulation has been observed. Several outbreaks on industrialised sow breeding units actually remained stationary. The occurrence of the disease may be favoured by a number of factors which are conducive to accumulation of Clostridium perfringens Type C in a given stock. Group keeping of pregnant sows, simultaneous farrowing of larger groups of sows, group treatment of nursed piglets, using neomycin, chloramphenicol, oxytetracycline, and other antibiotics to which Clostridium perfringens is primarily resistant or has acquired resistance in the course of time are some of those contributive factors. Transmission of Clostridium perfringens Type C through feedstuff is possible, though it would lead to a real outbreak only by high intensity of the contamination, and it played a minor role in proliferation of the disease. 3479 Clostridium perfringens strains were isolated from 9,481 animals, both clinically intact and after death, with 30 species being included. Type classification revealed 2454 strains of Type A (70 per cent), 204 of Type D (5.88 per cent), 164 of Type C (four per cent), and 48 of Type B (1.34 per cent). There were 688 atoxic strains (17 per cent). Swine is the major carrier of Clostridium perfringens Type C, with 87 per cent of all Clostridium perfringens Type C strains having been isolated from swine. Swine was followed by fowl (four per cent), sheep (four per cent), cattle, rabbit, and dog (1.27 per cent each). Clostridium perfringens Type C was obtained from the faeces of clinically intact sows in seven instances, including two cases with sows (0.46 per cent) from farms with no previous record of necrotising enteritis.

Animals↗

[Biodiversity of Capillariinae].

The subfamily Capillariinae includes about 300 species of nematodes parasitizing all groups of vertebrates. Taxonomy and systematics of this parasites have been changed many times because of a difficulty in designation of particular species' features. That's why there are a lot of synonyms in this group. Nowadays most authors accept the systematics, of Capillariinae according to Moravec. Biology and ecology of species parasitizing breeding birds and mammals is well known, however data relative to capillaria of wild animals are fragmentary. Capillariinae parasitize in various part of alimentary system: mainly in intestine, stomach, duodenum, rarely in oesophagus, rectum or bursa of Fabricius and liver as well as respiratory and excretory systems. Pathogenicity depends on localization of nematodes and the age of the hosts, and on infection intensity. Species recorded in human beings are: Aonchotheca philippinensis, Eucoleus aerophilus and Calodium hepaticum. They are a cause of intestinal, lung and hepatic capillariosis.

Animals↗

Genetic analysis of three different classification protocols for the evaluation of elbow dysplasia in German shepherd dogs.

OBJECTIVES: Three different scoring systems for elbow dysplasia and its radiographic signs were genetically evaluated in 2645 German shepherd dogs. METHODS: An animal model was used to estimate heritabilities and additive genetic and residual correlations for the three scoring systems: ED-SV, which is recommended by the International Elbow Working Group; ED-LA, developed by Lang and others; and ED-TH, proposed by Tellhelm. RESULTS: The effects of sex, age at examination and the correlation between the two factors were significant for all three scoring systems. Heritability estimates (se) were 0.18 (0.04) for ED-SV, 0.11 (0.03) for ED-LA and 0.16 (0.04) for ED-TH. The additive genetic correlations among the different single criteria for elbow dysplasia and the different elbow dysplasia scores were between 0.68 and 0.98, except for the criteria ununited anconeal process and osteochondrosis dissecans of the trochlea humeri, which were mostly genetically negatively correlated to the other radiological criteria. CLINICAL SIGNIFICANCE: The elbow dysplasia scores were determined by two genetically different traits. The possibilities for selecting German shepherd dogs with respect to elbow dysplasia might be improved by taking into account these two traits in the prediction of breeding values.

Age Factors↗

Diversity among Cynodon accessions and taxa based on DNA amplification fingerprinting.

The genus Cynodon (Gramineae), comprised of 9 species, is geographically widely distributed and genetically diverse. Information on the amounts of molecular genetic variation among and within Cynodon taxa is needed to enhance understanding of phylogenetic relations and facilitate germplasm management and breeding improvement efforts. Genetic relatedness among 62 Cynodon accessions, representing eight species, was assessed using DNA amplification fingerprinting (DAF). Ten 8-mer oligonucleotides were used to amplify specific Cynodon genomic sequences. The DNA amplification products of individual accessions were scored for presence (1) or absence (0) of bands. Similarity matrices were developed and the accessions were grouped by cluster (UPGMA) and principal coordinate analysis. Analyses were conducted within ploidy level (2x = 18 and 4x = 36) and over ploidy levels. Each primer revealed polymorphic loci among accessions within species. Of 539 loci (bands) scored, 496 (92%) were polymorphic. Cynodon arcuatus was clearly separated from other species by numerous monomorphic bands. The strongest species similarities were between C. aethiopicus and C. arcuatus, C. transvaalensis and C. plectostachyus, and C. incompletus and C. nlemfuensis. Intraspecific variation was least for C. aethiopicus, C. arcuatus, and C. transvaalensis, and greatest for C. dactylon. Accessions of like taxonomic classification were generally clustered, except the cosmopolitan C. dactylon var. dactylon and C. dactylon var. afganicus. Within taxa, accessions differing in chromosome number clustered in all instances indicating the 2x and 4x forms to be closely related. Little, if any, relationship was found between relatedness as indicated by the DAF profiles and previous estimates of hybridization potential between the different taxa.

Base Sequence↗

Excremental androgen metabolite concentrations and gonad sizes in temperate zone vs. tropical Stonechats (Saxicola torquata ssp.).

Many songbirds in the temperate zones have comparatively short breeding seasons and are migratory. This often implies high breeding synchrony and competition for food, space, and mates. Tropical birds, in contrast, tend to be resident and react more flexibly to a more variable onset of environmental conditions conducive for breeding. Therefore, it can be expected that androgen metabolite concentrations in breeding males vary among birds from different latitudes. Studies on tropical birds, however, have revealed inconsistent results suggesting that additional factors not directly related to latitude, modify hormone levels. Furthermore, there is a potential for a phylogenetic bias when comparing birds of different taxonomic groups. In the present study, we compared androgen metabolite concentrations among closely related taxa of hand-raised male stonechats originating from tropical and temperate-zone populations in Kenya (0 degrees latitude), Kazakhstan (52 degrees N), and Ireland (52 degrees N), which differ partly in latitude of their provenance but also in the length of their breeding season (birds from Kazakhstan vs. Ireland). Hand-raised birds were housed in their natural photoperiod under otherwise identical environmental conditions. Androgen levels were determined from excrements to reduce disturbance. All three groups demonstrated a seasonal cycle of androgen metabolite concentrations concomitant with testis growth. Peak androgen metabolite concentrations were significantly lower in Kenyan stonechats compared to Kazakh stonechats. Irish birds had intermediate concentrations. Differences between Kazakh and Kenyan stonechats correlate with latitude, but data from the Irish population suggest the involvement of factors not directly related to latitude.

Adaptation, Physiological↗

Deletion (8)(q22) as the only chromosomal abnormality in a patient with RAEB-t with progression to acute myelocytic leukemia.

Cytogenetic investigation of the bone marrow cells of an 88-year-old woman with refractory anemia with an excess of blasts in transformation with progression to acute myelocytic leukemia (AML), FAB classification M4, revealed a deleted chromosome #8 with the breakpoint at band q22 as the sole abnormality. This breakpoint is the same as that in t(8;21)(q22;q22), mostly found in patients with AML. This finding is discussed in relation to the possible oncogenesis of AML, which in this case may mean that the deletion of chromosome #8 at band 8q22 and the resultant loss of genetic material with possible antioncogenic activity is the critical event leading to malignant transformation in AML and not the translocation of the end of 21q next to 8q.

Aged↗

Tracing the pathways of neotropical migratory shorebirds using stable isotopes: a pilot study.

We evaluated the potential use of stable isotopes to establish linkages between the wintering grounds and the breeding grounds of the Pectoral Sandpiper (Calidris melanotos), the White-rumped Sandpiper (Calidris fuscicollis), the Baird's Sandpiper (Calidris bairdii), and other Neotropical migratory shorebird species (e.g., Tringa spp.). These species molt their flight feathers on the wintering grounds and hence their flight feathers carry chemical signatures that are characteristic of their winter habitat. The objective of our pilot study was to assess the feasibility of identifying the winter origin of individual birds by: (1) collecting shorebird flight feathers from several widely separated Argentine sites and analyzing these for a suite of stable isotopes; and 2) analyzing the deuterium and 18O isotope data that were available from precipitation measurement stations in Argentina. Isotopic ratios (delta13C, delta15N and delta34S) of flight feathers were significantly different among three widely separated sites in Argentina during January 2001. In terms of relative importance in separating the sites, delta34S was most important, followed by delta15N, and then delta13C. In the complete discriminant analysis, the classification function correctly predicted group membership in 85% of the cases (jackknifed classification matrix). In a stepwise analysis delta13C was dropped from the solution, and site membership was correctly predicted in 92% of cases (jackknifed matrix). Analysis of precipitation data showed that both deltaD and delta18O were significantly related to both latitude and longitude on a countrywide scale (p < 0.001). Other variables, month, altitude, explained little additional variation in these isotope ratios. Several issues were identified that will likely constrain the degree of accuracy one can expect in predicting the geographic origin of birds from Argentina. There was unexplained variation in isotope ratios within and among the different wing feathers from individual birds. Such variation may indicate that birds are not faithful to a local site during their winter stay in Argentina. There was significant interannual variation in the deltaD and delta18O of precipitation. Hence, specific locations may not have a constant signature for some isotopes. Moreover, the fractionation that occurs in wetlands due to evaporation significantly skews local deltaD and delta18O values, which may undermine the strong large-scale gradients seen in the precipitation data. We are continuing the research with universities in Argentina with a focus on expanding the breadth of feather collection and attempting to resolve the identified issues.

Animals↗

The harmonic-to-noise ratio applied to dog barks.

Dog barks are typically a mixture of regular components and irregular (noisy) components. The regular part of the signal is given by a series of harmonics and is most probably due to regular vibrations of the vocal folds, whereas noise refers to any nonharmonic (irregular) energy in the spectrum of the bark signal. The noise components might be due to chaotic vibrations of the vocal-fold tissue or due to turbulence of the air. The ratio of harmonic to nonharmonic energy in dog barks is quantified by applying the harmonics-to-noise ratio (HNR). Barks of a single dog breed were recorded in the same behavioral context. Two groups of dogs were considered: a group of ten healthy dogs (the normal sample), and a group of ten unhealthy dogs, i.e., dogs treated in a veterinary clinic (the clinic sample). Although the unhealthy dogs had no voice disease, differences in emotion or pain or impacts of surgery might have influenced their barks. The barks of the dogs were recorded for a period of 6 months. The HNR computation is based on the Fourier spectrum of a 50-ms section from the middle of the bark. A 10-point moving average curve of the spectrum on a logarithmic scale is considered as estimator of the noise level in the bark, and the maximum difference of the original spectrum and the moving average is defined as the HNR measure. It is shown that a reasonable ranking of the voices is achievable based on the measurement of the HNR. The HNR-based classification is found to be consistent with perceptual evaluation of the barks. In addition, a multiparametric approach confirms the classification based on the HNR. Hence, it may be concluded that the HNR might be useful as a novel parameter in bioacoustics for quantifying the noise within a signal.

Animal Communication↗

Trichinella pseudospiralis populations of the Palearctic region and their relationship with populations of the Nearctic and Australian regions.

Since few non-encapsulated isolates of Trichinella have been studied to date, their level of differentiation from encapsulated species and the taxonomic value of the observed polymorphisms remain to be determined. To this end, biological, biochemical and molecular data from 11 isolates of Trichinella pseudospiralis and one isolate of Trichinella papuae were examined using the broad group of encapsulated species and genotypes for comparison. Single-worm cross-breeding experiments and reproductivity capacity indices revealed F1 progeny only among T. pseudospiralis isolates from different zoogeographical regions, whereas no F1 were produced when T. pseudospiralis was crossed with T. papuae. Furthermore, unlike T. pseudospiralis, T. papuae failed to infect chickens. Comparative analysis of 12 allozymes revealed a single difference between Nearctic and Australian isolates of T. pseudospiralis, but substantial differences when compared with T. papuae (i.e. two unique and six diagnostic markers). Molecular studies involving mitochondrial-derived genes encoding cytochrome oxidase I and the large subunit ribosomal DNA indicated a high level of sequence similarity among T. pseudospiralis isolates; however, a concomitantly high level of variation was observed in expansion segment five of the genomic large subunit ribosomal DNAs among T. pseudospiralis isolates and between this species and T. papuae. Collectively, these results demonstrate high uniformity among isolates of T. pseudospiralis from Eurasia and polymorphism among isolates of T. pseudospiralis belonging to different zoogeographical regions; the results corroborate the classification of T. papuae as a differentiated species.

Animals↗

Bicipital tendinitis and tenosynovitis in the dog: a study of 15 cases.

AIM: To describe the clinical, radiographic, and sonographic features of 15 dogs with bicipital tendinitis and tenosynovitis, classify them according to cause, and evaluate the long-term efficacy of treatment. METHODS: Dogs exhibiting forelimb lameness with pain localised to the biceps tendon were included in the study. Sonographic examination of the tendon and tendon sheath, and radiographic examination including positive contrast arthrograms of the shoulder joint were performed, and assessed for features consistent with biceps tendon disease. In some cases, synovial-fluid analysis and surgical investigation were also undertaken. The causes of the conditions were classified as either traumatic, mechanical, neoplastic or inflammatory. Dogs were treated conservatively with rest and anti-inflammatory drugs, or surgically by either transection of the transverse humeral ligament or tenodesis of the biceps tendon. Assessment of the effects of treatment was made by re-examination at six weeks and from information gained by telephone interview with the dog's owner at longer-term follow-up. RESULTS: Bicipital tendinitis and tenosynovitis were common causes of forelimb lameness in active, middle-aged or older, medium to large-breed dogs. The most sensitive physical tests for localising pain to the biceps apparatus were shoulder flexion with the elbow extended, focal digital pressure applied directly to the biceps origin, and the biceps retraction test. Sonographic assessment was found to be more sensitive than shoulder radiography or arthrography for characterising the lesion. Conservative treatment of 11 traumatic cases resulted in good or excellent function at long-term follow-up. One mechanical bicipital tendinitis secondary to mineral deposits within the supraspinatus tendon improved following transection of the transverse humeral ligament and removal of the deposits. One of two cases of inflammatory tendinitis/ tenosynovitis improved following tenodesis. One dog with neoplastic disease did not improve and was euthanased. CONCLUSIONS: The diagnosis of bicipital tendinitis and tenosynovitis requires a careful examination using a combination of physical tests. Of the ancillary tests, sonography was the most reliable, however information gained from all tests was useful in fully evaluating the biceps apparatus and shoulder joint. The classification system employed in this study was helpful in selecting a treatment protocol and determining the likely prognosis.

Journal Article↗

Plasma cell acid phosphatase score in multiple myeloma and related disorders.

A detailed classification of plasma cells stained for acid phosphatase activity is introduced. With this method, patients with multiple myeloma, non-myeloma gammopathies, reactive plasmacytosis and other diseases in which plasma cells are involved, were investigated. The results show that our method can discriminate between multiple myeloma and reactive plasmacytosis. The overlap between multiple myeloma and other monoclonal gammopathies is much smaller than observed in other studies. Surprisingly low levels of acid phosphatase activity were found in the cells from patients with lymphoplasmacytoid immunocytoma. It is concluded that the acid phosphatase score can be of value for studying disorders in which plasma cells are involved.

Acid Phosphatase↗

Molecular markers derived from RAPD, SCAR, and the conserved 18S rDNA sequences for classification and identification in Pyrus pyrifolia and P. communis.

We generated RAPD, SCAR, and conserved 18S rDNA markers for classifying and identifying cultivars of Pyrus pyrifolia (Japanese pear) and P. communis (European pear). PCR amplification with selected specific primers-LCH327UP and LCH327DOWN-was performed using DNA extracted from 25 P. pyrifolia and P. communis cultivars. The 1,380-bp fragment was amplified from P. communis cvs. Beurre Giffard, Cascade, Conference, Clapp's Favorite, Packhams Triumph, and Winter Nelis. RAPD has only a dominant single band of 1,380-bp, however, SCAR has one or more band of the same size. Amplification involving sequence-specific primer pairs LCH346UP and LCH346DOWN resulted in a loss of polymorphism. The 1,190-bp fragment was amplified from all P. pyrifolia cultivars. The conserved sequences of the 18S rDNA fragment of 25 pear cultivars were amplified and analyzed with 42 restriction enzymes. Compared with P. pyrifolia cultivars, they lacked the restriction enzyme site of KpnI and had one less RsaI site. Cultivar Gamcheonbae had a specific PstI restriction site, while cvs. Mansoo and Conference pear digested with AluI showed a different presentation than other cultivars. For the Okusankichi and Shinil pears TaqI was best marker for identification in P. pyrifolia. These results can be adopted for identifying pear cultivars; to date there is no standard marker for identifying the cultivars of fruit trees in Korean fruit tree breeding programs.

Conserved Sequence↗