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1.
Coyotes (Canis latrans) have colonized northeastern North America only within the past 10-80 yr. We examined feces of coyotes in 2000-01 at three sites in New York (USA) to survey parasites in the region. Two cestodes, nine nematodes, five protozoa, one trematode, and two arthropods were identified from 145 coyote fecal samples. Parasite component community diversity was higher (n = 16 species) in southern New York than in middle and northern sites (nine species each) and infracommunity species richness was greater in southern New York than at the other sites. These differences may reflect the variable diets of coyotes, as well as recent colonization of the region and the mixing of component communities from expanding coyote populations.  相似文献   

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The genetics of adaptation is a key problem in evolutionary biology. Pocket gophers of the species Thomomys bottae provide one of the most striking examples of coat color variation in mammals. Dorsal pelage color is strongly correlated with soil color across the range of the species, presumably reflecting the selective pressure exerted by predation. To investigate the genetic basis of coat color variation in T. bottae, we cloned and sequenced the melanocortin-1 receptor locus (Mc1r), a candidate pigmentation gene, in 5 dark and 5 light populations of the species. Our results show that, in contrast to many other species of mammals and other vertebrates, coding variation at Mc1r is not the main determinant of coat color variation in T. bottae. These results demonstrate that similar phenotypic variation may have a different genetic basis among different mammalian species.  相似文献   

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We found a new coat color mutant in a population of Japanese wild mice (Mus musculus molossinus) and called the trait tawny. The tawny mutant is characterized by a light yellowish brown coat color. The tawny hair has a so-called agouti pattern, but the yellow band is greatly lengthened. There are no differences between the tawny and wildtype hairs in size and the number of melanosomes. Genetic analyses revealed that the tawny trait is an autosomal recessive and its gene is located in the distal region on Chromosome 8 between the microsatellite markers D8Mit87 and D8Mit122. An allelism test indicated the tawny mutant gene to be a new allele at the Mc1r locus and dominant to the recessive yellow (Mc1re). The proposed gene symbol for the tawny is Mc1rtaw.  相似文献   

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Prasolova LA  Trapezov OV 《Genetika》2007,43(7):982-986
The morphological patterns of hair pigmentation (the size and shape of pigment granules and their distribution among layers) have been studied in four compound coat color forms of the American mink: moil-sapphire also known as violet (genotype m/m a/a p/p); moil-silver or sage (genotype m/m p/p); the color form determined by genotype m/+ a/a; and platinum leopard (S(k)/+ a/+ p/p). The hair pigmentation pattern specific for each coat color form and its difference from the standard coat color of the American mink (genotype +/+) has been determined. The possible mechanisms of the phenotypic expression of the nonallelic genes contributing to the described compound color forms are discussed.  相似文献   

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Akey JM  Wang H  Xiong M  Wu H  Liu W  Shriver MD  Jin L 《Human genetics》2001,108(6):516-520
The melanocortin-1 receptor (MC1R) and P gene product are two important components of the human pigmentary system that have been shown to be associated with red hair/fair skin and cause type II oculocutaneous albinism, respectively. However, their contribution to inter-individual variation at the population level is not well defined. To this end, we genotyped 3 single nucleotide polymorphisms (SNPs) in the MC1R gene (Arg67Gln, Gln163Arg, Val92Met) and 2 SNPs in the P gene (IVS 13-15 and Gly780Gly) in 184 randomly ascertained Tibetan subjects, whose skin color was measured as a quantitative trait by reflective spectroscopy. Single locus analyses failed to demonstrate an association between any of the 5 SNPs and skin pigmentation. However, when an epistatic model was applied to the data, a significant gene-gene interaction was identified between Val92Met in MCIR and IVS13-15 in the P gene (F=2.43; P=0.0105). We also discuss the possible mechanisms of how gene interactions arise in signal transduction pathways.  相似文献   

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The morphological patterns of hair pigmentation (the size and shape of pigment granules and their distribution among layers) have been studied in four compound coat color forms of the American mink: moil-sapphire also known as violet (genotype m/m a/a p/p); moil-silver or sage (genotype m/m p/p); the color form determined by genotype m/+ a/a; and platinum leopard (S k /+ a/+ p/p). The hair pigmentation pattern specific for each coat color form and its difference from the standard coat color of the American mink (genotype +/+) has been determined. The possible mechanisms of the phenotypic expression of the nonallelic genes contributing to the described compound color forms are discussed.  相似文献   

10.
We have characterized two mutations in the MC1R gene of the blue variant of the arctic fox (Alopex lagopus) that both incorporate a novel cysteine residue into the receptor. A family study in farmed arctic foxes verified that the dominant expression of the blue color phenotype cosegregates completely with the allele harboring these two mutations. Additionally to the altered pigment synthesis, the blue fox allele suppresses the seasonal change in coat color found in the native arctic fox. Consequently, these findings suggest that the MC1R/agouti regulatory system is involved in the seasonal changes of coat color found in arctic fox.  相似文献   

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S Chen  K Xue  L Xu  G Ma  J Wu 《Mutation research》2001,458(1-2):41-47
Cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) metabolize tobacco-related carcinogens. To investigate the prevalence of CYP1A1 and GSTM1, and their association with increased risk of lung carcinoma in Chinese, allele-specific PCR and multiplex PCR technique were employed to identify the genotypes of CYP1A1 and GSTM1 in a case-control study of 106 lung carcinoma patients with histopathological diagnosis and 106 matched controls free of malignancy in Jiangsu Province, China. Logistic regression analysis was performed to calculate the odds ratio (OR) and 95% confidence intervals (CI). The results showed that individuals with GSTM1 null, and the combined GSTM1 null/CYP1A1 Ile/Val or GSTM1 null/CYP1A1 Val/Val had an elevated risk of lung carcinoma, with the OR, 1.92 (P=0.02; CI, 1.07-3.46), 3.27 (P=0.01; CI, 1.23-8.84) and 9.33 (P=0.04; CI, 1.01-217.42), respectively. Light smokers (<30 pack-years) carrying GSTM1 null genotype were shown to have the increased risk to lung carcinoma (OR=3.47; CI, 1.13-7.57). Our study suggested that the null GSTM1 genotype, independently or in combined with at least one Val allele of CYP1A1, might affect the genetic susceptibility for lung carcinoma in Chinese population.  相似文献   

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Polygalacturonase-inhibiting proteins (PGIPs) are plant cell wall glycoproteins that can inhibit fungal endopolygalacturonases (PGs). The PGIPs directly reduce the aggressive potential of PGs. Here, we isolated and functionally characterized three members of the pepper (Capsicum annuum) PGIP gene family. Each was up-regulated at a different time following stimulation of the pepper leaves by Phytophthora capcisi and abiotic stresses including salicylic acid, methyl jasmonate, abscisic acid, wounding and cold treatment. Purified recombinant proteins individually inhibited activity of PGs produced by Alternaria alternata and Colletotrichum nicotianae, respectively, and virus-induced gene silencing in pepper conferred enhanced susceptibility to P. capsici. Because three PGIP genes acted similarily in conferring resistance to infection by P. capsici, and because individually purified proteins showed consistent inhibition against PG activity of both pathogens, CaPGIP1 was selected for manipulating transgenic tobacco. The crude proteins from transgenic tobacco exhibited distinct enhanced resistance to PG activity of both fungi. Moreover, the transgenic tobacco showed effective resistance to infection and a significant reduction in the number of infection sites, number of lesions and average size of lesions in the leaves. All results suggest that CaPGIPs may be involved in plant defense response and play an important role in a plant’s resistance to disease.  相似文献   

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Backcross and F2 analyses have been carried out to determine the genetic basis of inheritance of three myosin light chain-1 variants present in the fast white muscle fibers of the domestic chicken. Two of the variants (types I and II) were described previously [Rushbrook, J. I., Yuan, A. I., and Stracher, A. (1982). Muscle Nerve 5:505], while the existence of the third (type III) is reported here. The results are consistent with an autosomal and allelic origin for the variants. A test linkage backcross to the muscular dystrophy gene am was found to be negative. This is the twelfth negative linkage result for the am gene.This work was supported by grants from the Muscular Dystrophy Association, Inc., and the National Institutes of Health (R23 HL27883) to Dr. Rushbrook and from the National Institutes of Health (R01 NS18438) to Dr. A. Stracher. It is a joint publication from the institutions listed below and is Scientific Contribution No. 1,070 from the Storrs Agricultural Experiment Station.  相似文献   

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Cantaloupe line CZW-30 containing coat protein gene constructs of cucumber mosaic cucumovirus (CMV), zucchini yellow mosaic potyvirus (ZYMV), and watermelon mosaic virus 2 potyvirus (WMV-2) was investigated in the field over two consecutive years for resistance to infections by CMV, ZYMV, and/or WMV-2. Resistance was evaluated under high disease pressure achieved by mechanical inoculations and/or natural challenge inoculations by indigenous aphid vectors. Across five different trials, homozygous plants were highly resistant in that they never developed systemic symptoms as did the nontransformed plants but showed few symptomatic leaves confined close to the vine tips. Hemizygous plants exhibited a significant delay (2–3 weeks) in the onset of disease compared to control plants but had systemic symptoms 9–10 weeks after transplanting to the field. Importantly, ELISA data revealed that transgenic plants reduced the incidence of mixed infections. Only 8% of the homozygous and 33% of the hemizygous plants were infected by two or three viruses while 99% of the nontransformed plants were mixed infected. This performance is of epidemiological significance. In addition, control plants were severely stunted (44% reduction in shoot length) and had poor fruit yield (62% loss) compared to transgenic plants, and most of their fruits (60%) were unmarketable. Remarkably, hemizygous plants yielded 7.4 times more marketable fruits than control plants, thus suggesting a potential commercial performance. This is the first report on extensive field trials designed to assess the resistance to mixed infection by CMV, ZYMV, and WMV-2, and to evaluate the yield of commercial quality cantaloupes that are genetically engineered.  相似文献   

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