共查询到20条相似文献,搜索用时 15 毫秒
1.
A. A. FERNANDEZ 《Journal of evolutionary biology》2010,23(2):386-396
The persistence of seemingly maladaptive genes in organisms challenges evolutionary biological thought. In Xiphophorus fishes, certain melanin patterns form malignant melanomas because of a cancer‐causing gene (Xiphophorus melanoma receptor kinase; Xmrk), which arose several millions years ago from unequal meiotic recombination. Xiphophorus melanomas are male biased and induced by androgens however male behaviour and Xmrk genotype has not been investigated. This study found that male X. cortezi with the spotted caudal (Sc) pattern, from which melanomas originate, displayed increased aggression in mirror image trials. Furthermore, Xmrk males (regardless of Sc phenotype) bit and performed more agonistic displays than Xmrk deficient males. Male aggressive response decreased when males viewed their Sc image as compared with their non‐Sc image. Collectively, these results indicate that Xmrk males experience a competitive advantage over wild‐type males and that intrasexual selection could be an important component in the evolutionary maintenance of this oncogene within Xiphophorus. 相似文献
2.
3.
Li HY Savage T Obermoeller RD Kazianis S Walter RB 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2002,133(4):581-595
Cytosine methylation appears to be established as an important DNA base modification involved in regulation of gene expression but is poorly understood from an evolutionary viewpoint. Xiphophorus progeny from inter-species crosses and backcrosses that are utilized in contemporary tumor induction studies were analyzed for cytosine methylation pattern inheritance using Southern blot analyses. Methylation patterns at CCGG sequences of 411 independent chromosomes in three distinct inter-species crosses were analyzed. In every case the non-recurrent parental methylation pattern remained unaltered for each of the genes studied, once introduced into the recurrent parental genetic background. Through F1 inter-species hybridization and succeeding meiosises leading to first generation (BC1) and second generation (BC2) backcross hybrid progeny, we demonstrate that parental species methylation patterns are stable. 相似文献
4.
Lisa L. Sramkoski Wesley N. McLaughlin Arielle M. Cooley David C. Yuan Alisha John Patricia J. Wittkopp 《Molecular ecology》2020,29(15):2840-2854
Phenotypic variation within a species is often structured geographically in clines. In Drosophila americana, a longitudinal cline for body colour exists within North America that appears to be due to local adaptation. The tan and ebony genes have been hypothesized to contribute to this cline, with alleles of both genes that lighten body colour found in D. americana. These alleles are similar in sequence and function to the allele fixed in D. americana's more lightly pigmented sister species, Drosophila novamexicana. Here, we examine the frequency and geographic distribution of these D. novamexicana‐like alleles in D. americana. Among alleles from over 100 strains of D. americana isolated from 21 geographic locations, we failed to identify additional alleles of tan or ebony with as much sequence similarity to D. novamexicana as the D. novamexicana‐like alleles previously described. However, using genetic analysis of 51 D. americana strains derived from 20 geographic locations, we identified one new allele of ebony and one new allele of tan segregating in D. americana that are functionally equivalent to the D. novamexicana allele. An additional 5 alleles of tan also showed marginal evidence of functional similarity. Given the rarity of these alleles, however, we conclude that they are unlikely to be driving the pigmentation cline. Indeed, phenotypic distributions of the 51 backcross populations analysed indicate a more complex genetic architecture, with diversity in the number and effects of loci altering pigmentation observed both within and among populations of D. americana. This genetic heterogeneity poses a challenge to association studies and genomic scans for clinal variation, but might be common in natural populations. 相似文献
5.
David L. Mitchell André A. Fernandez Rachel Garcia Lakshmi Paniker Kevin Lin Amanda Hanninen Kyle Zigelsky Matthew May Mark Nuttall Herng‐Hsiang Lo Maria D. Person Ryan Earley 《Pigment cell & melanoma research》2014,27(3):408-417
Using the Xiphophorus fish melanoma model, we show a strong male bias for sunlight‐induced malignant melanoma, consistent with that seen in the human population. To examine underlying factors, we exposed adult X. couchianus fish to a single, sublethal dose of UVB and measured circulating sex steroid hormones and expression of associated hormone receptor genes over a 24‐h period. We found that a single exposure had profound effects on circulating levels of steroid hormones with significant decreases for all free sex steroids at 6 and 24 h and increases in conjugated 2‐estradiol and 11‐ketotestosterone at 6 and 24 h, respectively. Whereas ARα expression increased in male and female skin, neither ARβ nor either of the ERs showed significant responses to UVB in either sex. The rapid response of male androgens and their receptors in the skin after UVB irradiation implicates hormones in the male bias of skin cancer and suggests that the photoendocrine response immediately after UV exposure may be relevant to melanomagenesis. 相似文献
6.
7.
Adult height is a risk factor in numerous human cancers that involve aberrant receptor tyrosine kinase (RTK) signalling. However, its importance is debated due to conflicting epidemiological studies and the lack of useful in vivo models. In Xiphophorus fishes (Platyfishes/Swordtails), a functional RTK, Xiphophorus melanoma receptor kinase (Xmrk), serves as the dominant oncogene and has been maintained for several million years despite being deleterious and in an extremely unstable genomic region. Here we show that the Xmrk genotype is positively correlated with standard length in male and female wild caught Xiphophorus cortezi sampled throughout their phylogeographic distribution. Histopathology confirms the occurrence of malignant melanomas in both sexes; however, melanoma incidence was extremely male biased. Furthermore, males collected with malignant melanomas in the field were significantly larger than both Xmrk males collected without melanomas and wildtype (Xmrk deficient) males. These results not only provide a novel selective mechanism for the persistence of the germline Xmrk oncogene but also create an innovative avenue of melanoma research within the Xiphophorus fishes. Wildlife cancer in natural systems is a growing concern, therefore, future research investigating life history characteristics associated with certain phenotypes and genotypes that predispose an individual to cancer will be fundamental to increasing our understanding of the evolutionary biology of cancer in nature as well as in humans. 相似文献
8.
9.
10.
11.
Sheng Wei Zhensheng Liu Yangkai Li Li‐E Wang Wei V. Chen Christopher I. Amos Jeffrey E. Lee Mark M. Iles Matthew H. Law Anne E. Cust Jennifer H. Barrett Grant W. Montgomery John Taylor Julia A. Newton Bishop Stuart MacGregor D. Timothy Bishop Graham J. Mann Nicholas K. Hayward Qingyi Wei 《Pigment cell & melanoma research》2013,26(3):392-401
To mine possibly hidden causal single‐nucleotide polymorphisms (SNPs) of melanoma, we investigated the association of SNPs in 76 M/G1 transition genes with melanoma risk using our published genome‐wide association study (GWAS) data set with 1804 melanoma cases and 1026 cancer‐free controls. We found multiple SNPs with P < 0.01 and performed validation studies for 18 putative functional SNPs in PSMB9 in two other GWAS data sets. Two SNPs (rs1351383 and rs2127675) were associated with melanoma risk in the GenoMEL data set (P = 0.013 and 0.004, respectively), but failed in validation using the Australian data set. Genotype–phenotype analysis revealed these two SNPs were significantly correlated with mRNA expression level of PSMB9. Further experiments revealed that SNP rs2071480, which is in high LD with rs1351383 and rs2127675, may have a weak effect on the promoter activity of PSMB9. Taken together, our data suggested that functional variants in PSMB9 may contribute to melanoma susceptibility. 相似文献
12.
Introgression of Pi2 and Pi5 Genes for Blast (Magnaporthe oryzae) Resistance in Rice and Field Evaluation of Introgression Lines for Resistance and Yield Traits
下载免费PDF全文
![点击此处可从《Journal of Phytopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Prashanthi Sagar KrishnaMurthy Dnyaneshwar B. Deshmukh Kakanur Jagadeesh Yashvanth Kumar Santosh Patil Shridevi Jakkeral Gangappa Hanamaratti Nemappa Uday D. Singh Mukund Variar Rajeev Rathour Gopalakrishnan Subbaiyan Ashok K. Singh Tilak Raj Sharma 《Journal of Phytopathology》2017,165(6):397-405
Blast caused by Magnaporthe oryzae is the most devastating disease causing significant loss in rice production. The destructive nature of the disease is mainly due to the genetic plasticity of M. oryzae which complicates the breeding strategies. Blast can be effectively managed by the deployment of R genes. In this study, broad‐spectrum blast resistance genes Pi2 and Pi5 were introgressed independently into popular but blast susceptible rice variety, Samba Mahsuri (BPT5204) by applying marker‐assisted backcross breeding approach. Tightly linked markers AP5930 for Pi2 and 40N23r for Pi5 gene were used in foreground selection. Background selection helped to identify the lines with maximum recovery of recurrent parent genome (RPG). The RPG recovery in Pi2 introgression lines was up to 90.17 and 91.46% in Pi5 lines. Homozygous introgression lines in BC3F4 generation carrying Pi2 and Pi5 gene were field evaluated for blast resistance, yield per se and yield‐related traits. The lines showed resistance to leaf and neck blast in multilocation field evaluation. Improved BPT5204 lines with improvement for blast resistance were on par with original BPT5204 in terms of grain yield and grain features. 相似文献
13.
Marianne Berwick Jamie MacArthur Irene Orlow Peter Kanetsky Colin B. Begg Li Luo Anne Reiner Ajay Sharma Bruce K. Armstrong Anne Kricker Anne E. Cust Loraine D. Marrett Stephen B. Gruber Hoda Anton‐Culver Roberto Zanetti Stefano Rosso Richard P. Gallagher Terence Dwyer Alison Venn Klaus Busam Lynn From Kirsten White Nancy E. Thomas the GEM Study Group 《Pigment cell & melanoma research》2014,27(3):485-488
14.
Adriana Sanna Katja Harbst Iva Johansson Gustav Christensen Martin Lauss Shamik Mitra Frida Rosengren Jari Hkkinen Johan Vallon‐Christersson Hkan Olsson sa Ingvar Karolin Isaksson Christian Ingvar Kari Nielsen Gran Jnsson 《Pigment cell & melanoma research》2020,33(3):480-489
Chronic sun‐damaged (CSD) melanoma represents 10%–20% of cutaneous melanomas and is characterized by infrequent BRAF V600E mutations and high mutational load. However, the order of genetic events or the extent of intra‐tumor heterogeneity (ITH) in CSDhigh melanoma is still unknown. Ultra‐deep targeted sequencing of 40 cancer‐associated genes was performed in 72 in situ or invasive CMM, including 23 CSDhigh cases. In addition, we performed whole exome and RNA sequencing on multiple regions of primary tumor and multiple in‐transit metastases from one CSDhigh melanoma patient. We found no significant difference in mutation frequency in melanoma‐related genes or in mutational load between in situ and invasive CSDhigh lesions, while this difference was observed in CSDlow lesions. In addition, increased frequency of BRAF V600K, NF1, and TP53 mutations (p < .01, Fisher's exact test) was found in CSDhigh melanomas. Sequencing of multiple specimens from one CSDhigh patient revealed strikingly limited ITH with >95% shared mutations. Our results provide evidence that CSDhigh and CSDlow melanomas are distinct molecular entities that progress via different genetic routes. 相似文献
15.
Ana M. Arance Marcelo Sánchez Gemma Tell‐Marti Miriam Potrony Carles Conill Remco van Doorn Stefan Dentro Nelleke A. Gruis Pippa Corrie Vivek Iyer Carla Daniela Robles‐Espinoza Joan A. Puig‐Butille David J. Adams 《Pigment cell & melanoma research》2017,30(3):307-316
Melanoma in young children is rare; however, its incidence in adolescents and young adults is rising. We describe the clinical course of a 15‐year‐old female diagnosed with AJCC stage IB non‐ulcerated primary melanoma, who died from metastatic disease 4 years after diagnosis despite three lines of modern systemic therapy. We also present the complete genomic profile of her tumour and compare this to a further series of 13 adolescent melanomas and 275 adult cutaneous melanomas. A somatic BRAFV600E mutation and a high mutational load equivalent to that found in adult melanoma and composed primarily of C>T mutations were observed. A germline genomic analysis alongside a series of 23 children and adolescents with melanoma revealed no mutations in known germline melanoma‐predisposing genes. Adolescent melanomas appear to have genomes that are as complex as those arising in adulthood and their clinical course can, as with adults, be unpredictable. 相似文献
16.
Jacquelin DeFaveri Takahito Shikano Yukinori Shimada Juha Merilä 《Molecular ecology》2013,22(18):4811-4828
Populations of widespread marine organisms are typically characterized by a low degree of genetic differentiation in neutral genetic markers, but much less is known about differentiation in genes whose functional roles are associated with specific selection regimes. To uncover possible adaptive population divergence and heterogeneous genomic differentiation in marine three‐spined sticklebacks (Gasterosteus aculeatus), we used a candidate gene‐based genome‐scan approach to analyse variability in 138 microsatellite loci located within/close to (<6 kb) functionally important genes in samples collected from ten geographic locations. The degree of genetic differentiation in markers classified as neutral or under balancing selection—as determined with several outlier detection methods—was low (FST = 0.033 or 0.011, respectively), whereas average FST for directionally selected markers was significantly higher (FST = 0.097). Clustering analyses provided support for genomic and geographic heterogeneity in selection: six genetic clusters were identified based on allele frequency differences in the directionally selected loci, whereas four were identified with the neutral loci. Allelic variation in several loci exhibited significant associations with environmental variables, supporting the conjecture that temperature and salinity, but not optic conditions, are important drivers of adaptive divergence among populations. In general, these results suggest that in spite of the high degree of physical connectivity and gene flow as inferred from neutral marker genes, marine stickleback populations are strongly genetically structured in loci associated with functionally relevant genes. 相似文献
17.
18.
Joanna Kaplon Cornelia Hömig‐Hölzel Linda Gao Katrin Meissl Els M. E. Verdegaal Sjoerd H. van der Burg Remco van Doorn Daniel S. Peeper 《Pigment cell & melanoma research》2014,27(4):640-652
The activation of oncogenes in primary cells blocks proliferation by inducing oncogene‐induced senescence (OIS), a highly potent in vivo tumor‐suppressing program. A prime example is mutant BRAF, which drives OIS in melanocytic nevi. Progression to melanoma occurs only in the context of additional alteration(s) like the suppression of PTEN, which abrogates OIS. Here, we performed a near‐genomewide short hairpin (sh)RNA screen for novel OIS regulators and identified by next generation sequencing and functional validation seven genes. While all but one were upregulated in OIS, depletion of each of them abrogated BRAFV600E‐induced arrest. With genome‐wide DNA methylation analysis, we found one of these genes, RASEF, to be hypermethylated in primary cutaneous melanomas but not nevi. Bypass of OIS by depletion of RASEF was associated with suppression of several senescence biomarkers including senescence‐associated (SA)‐β‐galactosidase activity, interleukins, and tumor suppressor p15INK4B. Restoration of RASEF expression inhibited proliferation. These results illustrate the power of shRNA OIS bypass screens and identify a potential novel melanoma suppressor gene. 相似文献
19.
Laura Toppino Giampiero Valè Giuseppe Leonardo Rotino 《Molecular breeding : new strategies in plant improvement》2008,22(2):237-250
The two eggplant relatives Solanum aethiopicum gr. Gilo and Solanum aethiopicum gr. Aculeatum (=Solanum integrifolium) carry resistance to the fungal wilt disease caused by Fusarium oxysporum f. sp. melongenae, a worldwide soil-borne disease of eggplant. To introgress the resistance trait into cultivated eggplant, the tetraploid
somatic hybrids S. melongena + S. aethiopicum and S. melongena + S.
integrifolium were used. An inheritance study of the resistance was performed on advanced anther culture-derived androgenetic backcross
progenies from the two somatic hybrids. The segregation fitted a 3 resistant (R): 1 susceptible (S) ratio in the selfed populations
and a 1R:1S ratio in the backcross progenies for the trait derived from S. aethiopicum and S. integrifolium. These ratios are consistent with a single gene, which we designated as Rfo-sa1, controlling the resistance to Fusarium oxysporum f. sp. melongenae. The allelic relationship between the resistance genes from S. aethiopicum and S. integrifolium indicate that these two genes are alleles of the same locus. Bulked Segregant Analysis (BSA) was performed with RAPD markers
on the BC3/BC5 resistant advanced backcross progenies, and three RAPD markers associated with the resistance trait were identified. Cleaved
Amplified Polymorphic Sequences (CAPSs) were subsequently obtained on the basis of the amplicon sequences. The evaluation
of the efficiency of these markers in predicting the resistant phenotype in segregating progenies revealed that they represent
useful tools for indirect selection of Fusarium resistance in eggplant. 相似文献
20.
The Tianzhu white yak, a domestic yak indigenous to the Qilian Mountains, migrated inland from the Qinghai‐Tibet Plateau. Specific ecological and long‐term artificial selection influenced the evolution of its pure white coat and physiological characteristics. Therefore, it is not only a natural population that represents a genomic selective region of environmental adaptability but is also an animal model for studying the pigmentation of the yak coat. A total of 24 261 829 variants, including 22 445 252 SNPs, were obtained from 29 yaks by genome‐wide re‐sequencing. According to the results of a selective sweep analysis of Tianzhu white yak in comparison to Tibetan yaks, nine candidate genes under selection in Tianzhu white yak were identified by combining π, Tajima's D, πA/πB and FST statistics, with threshold standards of 5%. These genes include PDCD1, NUP210, ABCG8, NEU4, LOC102287650, D2HGDH, COL4A1, RTP5 and HDAC11. Five of the nine genes were classified into 12 molecular signaling pathways, and most of these signaling pathways are involved in environmental information processing, organismal systems and metabolism. A majority of these genes has not been implicated in previous studies of yak coat color and high‐altitude animals. Our findings are helpful not only for explaining the molecular mechanism of yak coat pigmentation but also for exploring the genetic changes in Tianzhu white yak due to environmental adaptation. 相似文献