RESUMO
Genome-wide association mapping using dense marker sets has identified some nucleotide variants affecting complex traits that have been validated with fine-mapping and functional analysis. However, many sequence variants associated with complex traits in maize have small effects and low repeatability. In contrast to genome-wide association study (GWAS), genomic prediction (GP) is typically based on models incorporating information from all available markers, rather than modeling effects of individual loci. We considered methods to integrate results of GWASs into GP models in the context of multiple interconnected families. We compared association tests based on a biallelic additive model constraining the effect of a single-nucleotide polymorphism (SNP) to be equal across all families in which it segregates to a model in which the effect of a SNP can vary across families. Association SNPs were then included as fixed effects into a GP model that also included the random effects of the whole genome background. Simulation studies revealed that the effectiveness of this joint approach depends on the extent of polygenicity of the traits. Congruent with this finding, cross-validation studies indicated that GP including the fixed effects of the most significantly associated SNPs along with the polygenic background was more accurate than the polygenic background model alone for moderately complex but not highly polygenic traits measured in the maize nested association mapping population. Individual SNPs with strong and robust association signals can effectively improve GP. Our approach provides a new integrative modeling approach for both reliable gene discovery and robust GP.
Assuntos
Estudos de Associação Genética , Genética Populacional , Genômica/métodos , Modelos Genéticos , Zea mays/genética , Simulação por Computador , Genótipo , Herança Multifatorial , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características QuantitativasRESUMO
Quantitative trait locus (QTL) mapping has been used to dissect the genetic architecture of complex traits and predict phenotypes for marker-assisted selection. Many QTL mapping studies in plants have been limited to one biparental family population. Joint analysis of multiple biparental families offers an alternative approach to QTL mapping with a wider scope of inference. Joint-multiple population analysis should have higher power to detect QTL shared among multiple families, but may have lower power to detect rare QTL. We compared prediction ability of single-family and joint-family QTL analysis methods with fivefold cross-validation for 6 diverse traits using the maize nested association mapping population, which comprises 25 biparental recombinant inbred families. Joint-family QTL analysis had higher mean prediction abilities than single-family QTL analysis for all traits at most significance thresholds, and was always better at more stringent significance thresholds. Most robust QTL (detected in >50% of data samples) were restricted to one family and were often not detected at high frequency by joint-family analysis, implying substantial genetic heterogeneity among families for complex traits in maize. The superior predictive ability of joint-family QTL models despite important genetic differences among families suggests that joint-family models capture sufficient smaller effect QTL that are shared across families to compensate for missing some rare large-effect QTL.
Assuntos
Mapeamento Cromossômico/métodos , Ligação Genética , Modelos Genéticos , Zea mays/genética , Marcadores Genéticos , Genética Populacional , Locos de Características QuantitativasRESUMO
Crop species exhibit an astounding capacity for environmental adaptation, but genetic bottlenecks resulting from intense selection for adaptation and productivity can lead to a genetically vulnerable crop. Improving the genetic resiliency of temperate maize depends upon the use of tropical germplasm, which harbors a rich source of natural allelic diversity. Here, the adaptation process was studied in a tropical maize population subjected to 10 recurrent generations of directional selection for early flowering in a single temperate environment in Iowa, USA. We evaluated the response to this selection across a geographical range spanning from 43.05° (WI) to 18.00° (PR) latitude. The capacity for an all-tropical maize population to become adapted to a temperate environment was revealed in a marked fashion: on average, families from generation 10 flowered 20 days earlier than families in generation 0, with a nine-day separation between the latest generation 10 family and the earliest generation 0 family. Results suggest that adaptation was primarily due to selection on genetic main effects tailored to temperature-dependent plasticity in flowering time. Genotype-by-environment interactions represented a relatively small component of the phenotypic variation in flowering time, but were sufficient to produce a signature of localized adaptation that radiated latitudinally, in partial association with daylength and temperature, from the original location of selection. Furthermore, the original population exhibited a maladaptive syndrome including excessive ear and plant heights along with later flowering; this was reduced in frequency by selection for flowering time.
Assuntos
Adaptação Fisiológica/genética , Fotoperíodo , Seleção Genética , Zea mays/genética , Produtos Agrícolas/genética , Flores/fisiologia , Interação Gene-Ambiente , Genética Populacional , Modelos Lineares , Modelos Genéticos , Fenótipo , Temperatura , Zea mays/fisiologiaRESUMO
Appropriate selection of parents for the development of mapping populations is pivotal to maximizing the power of quantitative trait loci detection. Trait genotypic variation within a family is indicative of the family's informativeness for genetic studies. Accurate prediction of the most useful parental combinations within a species would help guide quantitative genetics studies. We tested the reliability of genotypic and phenotypic distance estimators between pairs of maize inbred lines to predict genotypic variation for quantitative traits within families derived from biparental crosses. We developed 25 families composed of ~200 random recombinant inbred lines each from crosses between a common reference parent inbred, B73, and 25 diverse maize inbreds. Parents and families were evaluated for 19 quantitative traits across up to 11 environments. Genetic distances (GDs) among parents were estimated with 44 simple sequence repeat and 2303 single-nucleotide polymorphism markers. GDs among parents had no predictive value for progeny variation, which is most likely due to the choice of neutral markers. In contrast, we observed for about half of the traits measured a positive correlation between phenotypic parental distances and within-family genetic variance estimates. Consequently, the choice of promising segregating populations can be based on selecting phenotypically diverse parents. These results are congruent with models of genetic architecture that posit numerous genes affecting quantitative traits, each segregating for allelic series, with dispersal of allelic effects across diverse genetic material. This architecture, common to many quantitative traits in maize, limits the predictive value of parental genotypic or phenotypic values on progeny variance.
Assuntos
Evolução Biológica , Variação Genética , Zea mays/genética , Genótipo , Endogamia , Fenótipo , Polimorfismo de Nucleotídeo Único , Valor Preditivo dos Testes , Locos de Características QuantitativasRESUMO
PREMISE OF THE STUDY: Teosinte species are the closest relatives of maize and represent an important but increasingly rare genetic resource for maize improvement and the study of evolution by domestication. Three morphologically and ecologically distinct teosinte populations were recently discovered in México. The taxonomic status of these rare and endangered populations was investigated by detailed comparisons to previously characterized wild Zea species. ⢠METHODS: Three new teosinte populations were compared to known teosinte taxa on the basis of morphological, ecogeographic, cytological, and molecular characteristics. Phenetic and phylogenetic analyses were performed using morphological and molecular data, respectively. ⢠KEY RESULTS: The newly discovered populations are distinct from each other and from other Zea species to represent three new entities based on their unique combinations of morphological, ecological, ploidy, and DNA markers. A perennial diploid population from Nayarit is distinguished by early maturing plants, and having male inflorescences with few tassel branches and long spikelets. A perennial tetraploid population from Michoacán is characterized by tall and late maturing plants, and having male inflorescences with many branches. An annual diploid population from Oaxaca is characterized by having male inflorescences with fewer branches and longer spikelets than those found in the sister taxa Z. luxurians and Z. nicaraguensis, plants with high thermal requirements, and very long seed dormancy. ⢠CONCLUSIONS: Evidence from multiple independent sources suggests placement of the three new populations of teosinte as distinct entities within section Luxuriantes of the genus Zea. However, more extensive DNA marker or sequence data are required to resolve the taxonomy of this genus.
Assuntos
Zea mays/classificação , Cromossomos de Plantas , Marcadores Genéticos , México , Filogenia , Zea mays/genéticaRESUMO
Maize yield per unit area has dramatically increased over time as have plant population densities, but the genetic basis for plant response to density is unknown as is its stability over environments. To elucidate the genetic basis of plant response to density in maize, we mapped QTL for plant density-related traits in a population of 186 recombinant inbred lines (RILs) derived from the cross of inbred lines B73 and Mo17. All RILs were evaluated for growth, development, and yield traits at moderate (50 000 plants per hectare) and high (100 000 plants per hectare) plant densities. The results show that genetic control of the traits evaluated is multigenic in their response to density. Five of the seven loci significant for final height showed statistical evidence for epistatic interactions. Other traits such as days to anthesis, anthesis-to-silking interval, barrenness, ears per plant, and yield per plant all showed statistical evidence for an epistatic interaction. Locus by density interactions are of critical importance for anthesis-to-silking interval, barrenness, and ears per plant. A second independent experiment to examine the stability of QTL for barrenness in a new environment clearly showed that the multilocus QTL were stable across environments in their differential response to density. In this verification experiment, the four-locus QTL was used to choose lines with the four unfavorable alleles and compare them with the lines with four favorable alleles and the effect was confirmed.
Assuntos
Locos de Características Quantitativas , Zea mays/genética , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Cruzamentos Genéticos , EndogamiaRESUMO
The intermated B73 x Mo17 (IBM) population, an advanced intercross recombinant inbred line population derived from a cross between the maize lines B73 (susceptible) and Mo17 (resistant), was evaluated in four environments for resistance to southern leaf blight (SLB) disease caused by Cochliobolus heterostrophus race O. Two environments were artificially inoculated, while two were not inoculated and consequently had substantially lower disease pressure. Four common SLB resistance quantitative trait loci (QTL) were identified in all environments, two in bin 3.04 and one each in bins 1.10 and 8.02/3. There was no significant correlation between disease resistance and days to anthesis. A direct comparison was made between SLB QTL detected in two populations, independently derived from the same parental cross: the IBM advanced intercross population and a conventional recombinant inbred line population. Several QTL for SLB resistance were detected in both populations, with the IBM providing between 5 and, in one case, 50 times greater mapping resolution.
Assuntos
Ascomicetos/fisiologia , Mapeamento Cromossômico , Flores/fisiologia , Doenças das Plantas/imunologia , Locos de Características Quantitativas/genética , Zea mays/genética , Zea mays/microbiologia , Cromossomos de Plantas/genética , Cruzamentos Genéticos , Flores/microbiologia , Imunidade Inata , Modelos Biológicos , Doenças das Plantas/genética , Fatores de TempoRESUMO
A 29-year-old pregnant patient, gravida 4, para 3, sought genetic counseling because of a daughter who had Down's syndrome. Amniotic fluid obtained by amniocentesis indicated the fetal karyotype to be 47,XXX. The pregnancy was terminated and the karyotype was confirmed by typing venous blood from the fetus and the finding of double Barr bodies in the histologic sections of fetal tissue.
Assuntos
Amniocentese , Aberrações dos Cromossomos Sexuais/diagnóstico , Aborto Induzido , Criança , Pré-Escolar , Síndrome de Down/genética , Feminino , Aconselhamento Genético , Humanos , Cariotipagem , Masculino , GravidezRESUMO
An Enterobius vermicularis within the parenchyma of the ovary is a rare phenomenon. We present a case and propose that the gravid female, after wandering from perianal skin into the vagina and then through the female genital passages, arrived at the ovary and entered a recently ruptured graafian follicle.
Assuntos
Doenças Ovarianas/etiologia , Oxiuríase/etiologia , Adulto , Feminino , Humanos , Masculino , Doenças Ovarianas/patologia , Ovário/patologia , Oxiuríase/patologiaRESUMO
In our efforts to overcome infertility and subjective complaints in young women with endometriosis, we have performed conservative surgical procedures upon 142 women 30 years of age or less. In these women, multiple endometriomata were resected from the pelvic peritoneum, one or both ovaries, the large and small bowel, and the appendix. In addition, uterine and ovarian suspension, bowel resection, appendectomy, myomectomy, and presacral neurectomy (PSN) were performed when indicated. Conception occurred in 70% of the women wishing to conceive; the highest rate was found among those who had developed endometriosis after a previous conception. Ovarian involvement seemed to reduce the conception rate by 10%. Uterine suspension and PSN did not affect conception but did provide a symptomatic relief. We conclude that early examination for endometriosis and aggressive surgical management is indicated in young women with demonstrable disease.
PIP: In our efforts to overcome infertility and subjective complaints in young women with endometriosis, we have performed conservative surgical procedures on 142 women age 30 or less. In these women, multiple endometriomata were resected from the pelvic peritoneum, 1 or both ovaries, the large and small bowel, and the appendix. In addition, uterine and ovarian suspension, bowel resection, appendectomy, myomectomy, and presacral neurectomy (PSN) were performed when indicated. Conception occurred in 70% of the women wishing to conceive; the highest rate was found among those who had developed endometriosis after a previous conception. Ovarian involvement seemed to reduce the conception rate by 10%. Uterine suspension and PSN did not affect conception but did provide symptomatic relief. We conclude that early examination for endometriosis and aggressive surgical management is indicated in young women with demonstrable disease.
Assuntos
Endometriose/cirurgia , Infertilidade Feminina/cirurgia , Neoplasias Pélvicas/cirurgia , Adolescente , Adulto , Endometriose/diagnóstico , Endometriose/patologia , Feminino , Humanos , Histerectomia , Infertilidade Feminina/etiologia , Infertilidade Feminina/patologia , Ovário/patologia , Ovário/cirurgia , Neoplasias Pélvicas/diagnóstico , Neoplasias Pélvicas/patologia , Complicações Pós-Operatórias/cirurgia , Gravidez , Útero/patologiaRESUMO
The specificity of gonadotropin binding was studied in fresh and frozen human corpora lutea. Ovine, bovine, and porcine luteinizing hormone (LH) competed with 125I-labeled human LH (125I-hLH) and 125I-labeled human chorionic gonadotropin (125I-hCG) for binding to tissue receptors in homogenates of human corpora lutea frozen for 3 to 12 months. In contrast, oLH, bLH, and pLH competed minimally for 125I-hLH and 125I-hCG binding sites in homogenates of fresh human corpora lutea. Ovine follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) did not compete in homogenates of fresh or frozen tissue. Competition of oLH and hCG for 125I-hCG binding sites at several dose levels in a homogenate of a fresh corpus luteum was studied. One hundred micrograms of oLH and ten nanograms of hCG gave an equivalent competition--a 10,000-fold difference in competitive potency. Only hCG competed with 125I-hCG for binding when the competition of oLH, bLH, pLH, oFSH, oTSH, hCG and hCG subunits, and hCG were compared at the 10-mug level in a homogenate of fresh human corpus luteum. The binding of 125I-labeled homologous human hormones by the corpus luteum was examined in a limited fashion. 125I-Prolactin did not bind to preparations of fresh stroma from a patient with polycystic ovaries nor did it bind to three separate preparations of fresh corpora luteum which did bind 125I-hCG. 125I-hTSH did not show significant binding to a fresh human corpus luteum preparation which did bind 125I-hCG. These studies indicate that the gonadotropin receptor of the fresh human corpus luteum possesses a unique species specificity and illustrate the importance of working with human corpora lutea in their most native state.
Assuntos
Gonadotropina Coriônica/metabolismo , Corpo Lúteo/metabolismo , Receptores de Superfície Celular , Ligação Competitiva , Feminino , Congelamento , Humanos , Radioisótopos do Iodo , Hormônio Luteinizante/metabolismo , Ligação Proteica , Especificidade da EspécieRESUMO
Seven N-substituted 1,2,3,4-tetrahydro-1- and three 2-naphthylamines were prepared and tested for local anesthetic activity in the rabbit corneal reflex test and the mouse sciatic nerve block test. At 0.1 and 1%, three 1-alkylamino compounds had durations of action comparable to that of tetracaine in the rabbit corneal reflex test and were considerably more potent than lidocaine. The other four 1-alkylamino derivatives were inactive or at best minimally active. The durations of action of 1% concentrations of the three 2-alkylamino compounds were equivalent to that of 1% lidocaine in the corneal reflex test. In the mouse sciatic nerve block test, the three active 1-alkylamino compounds were considerably longer acting than either tetracaine or lidocaine. Three 1-alkylamino and the three 2-alkylamino compounds showed toxicity equal to or greater than lidocaine, while two 1-alkylamino and two 2-alkylamino compounds showed toxicity equal to or greater than tetracaine by the intraperitoneal route in mice. N-Heptyl-1,2,3,4-tetrahydro-6-methoxy-1-naphthylamine methanesulfonate was the most promising local anesthetic in these series.
Assuntos
Anestésicos Locais , Naftalenos/farmacologia , Tetra-Hidronaftalenos/farmacologia , 1-Naftilamina/análogos & derivados , 1-Naftilamina/farmacologia , 1-Naftilamina/toxicidade , 2-Naftilamina/análogos & derivados , 2-Naftilamina/farmacologia , 2-Naftilamina/toxicidade , Animais , Córnea/efeitos dos fármacos , Feminino , Dose Letal Mediana , Camundongos , Camundongos Endogâmicos ICR , Coelhos , Reflexo/efeitos dos fármacos , Nervo Isquiático/efeitos dos fármacos , Tetra-Hidronaftalenos/toxicidadeAssuntos
Indenos/síntese química , Inibidores da Monoaminoxidase/síntese química , Naftalenos/síntese química , Animais , Encéfalo/enzimologia , Di-Hidroxifenilalanina/metabolismo , Di-Hidroxifenilalanina/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Indenos/farmacologia , Matemática , Camundongos , Inibidores da Monoaminoxidase/farmacologia , Naftalenos/farmacologia , Oxirredução , Oxotremorina/antagonistas & inibidores , Reserpina/antagonistas & inibidores , Relação Estrutura-Atividade , Triptaminas/metabolismoAssuntos
Antiparkinsonianos/síntese química , Indenos/síntese química , Naftalenos/síntese química , Quinolinas/síntese química , Analgésicos/farmacologia , Animais , Antiparkinsonianos/farmacologia , Sítios de Ligação , Dopamina/farmacologia , Indenos/farmacologia , Camundongos , Modelos Biológicos , Conformação Molecular , Inibidores da Monoaminoxidase/farmacologia , Contração Muscular/efeitos dos fármacos , Naftalenos/farmacologia , Oxotremorina/antagonistas & inibidores , Quinolinas/farmacologia , Receptores de Droga , Relação Estrutura-AtividadeRESUMO
A set of 89 near-isogenic lines (NILs) of maize was created using marker-assisted selection. Nineteen genomic regions, identified by restriction fragment length polymorphism loci and chosen to represent portions of all ten maize chromosomes, were introgressed by backcrossing three generations from donor line Tx303 into the B73 genetic background. NILs were genotyped at an additional 128 simple sequence repeat loci to estimate the size of introgressions and the amount of background introgression. Tx303 introgressions ranged in size from 10 to 150 cM, with an average of 60 cM. Across all NILs, 89% of the Tx303 genome is represented in targeted and background introgressions. The average proportion of background introgression was 2.5% (range 0-15%), significantly lower than the expected value of 9.4% for third backcross generation lines developed without marker-assisted selection. The NILs were grown in replicated field evaluations in two years to map QTLs for flowering time traits. A parallel experiment of testcrosses of each NIL to the unrelated inbred, Mo17, was conducted in the same environments to map QTLs in NIL testcross hybrids. QTLs affecting days to anthesis, days to silking, and anthesis-silk interval were detected in both inbreds and hybrids in both environments. The testing environments differed dramatically for drought stress, and different sets of QTLs were detected across environments. Furthermore, QTLs detected in inbreds were typically different from QTLs detected in hybrids, demonstrating the genetic complexity of flowering time. NILs can serve as a valuable genetic mapping resource for maize breeders and geneticists.
Assuntos
Mapeamento Cromossômico , Locos de Características Quantitativas , Zea mays/genética , Alelos , Cromossomos de Plantas , Cruzamentos Genéticos , Genes de Plantas , Marcadores Genéticos , Genótipo , Modelos Genéticos , Fenótipo , Polimorfismo de Fragmento de Restrição , Fatores de TempoRESUMO
Reciprocal effects are due to genetic effects of the parents (i.e. maternal and paternal effects), cytoplasmic effects and parent-of-origin effects. However, in Zea mays L. the extent to which reciprocal effects exist, or can be attributed to specific underlying components, remains an area of interest and study. Reciprocal effects have been reported by several investigators for various agronomic characters in different types of maize materials for grain and silage usage. Maize geneticists and breeders have recognized reciprocal effects as one source of genetic variability, but the lack of consistency in the observation of these effects, particularly due to stress conditions, has prevented a systematic exploitation of these effects in practical breeding programs. There is mounting molecular evidence for underlying mechanisms in maize, which could be responsible for both the existence, and the instability of reciprocal effects. In this study, we developed population of reciprocal backcrosses based on an initial set of recombinant inbred lines. This population was used for dissecting reciprocal effects into the underlying components (maternal, cytoplasmic and parent-of-origin) effects. We also developed statistical framework to identify and map contributions of specific nuclear chromosomal regions to reciprocal effects. We showed that differences in maternal parents, endosperm DNA and maternally transmitted factors collectively influence reciprocal effects early during the season, and that their influence diluted at later stages. We also found evidence that parent-of-origin effects in the sporophyte DNA existed at all stages and played an important role in establishing differences between reciprocal backcrosses at later developmental stages.
Assuntos
Variação Genética , Endogamia , Zea mays/genética , FenótipoRESUMO
Southern rust, caused by Puccinia polysora Underw, is a foliar disease that can severely reduce grain yield in maize (Zea mays L.). Major resistance genes exist, but their effectiveness can be limited in areas where P. polysora is multi-racial. General resistance could be achieved by combining quantitative and race-specific resistances. This would be desirable if the resistance alleles maintained resistance across environments while not increasing plant maturity. Recombinant inbred (RI) lines were derived from a cross between NC300, a temperate-adapted all-tropical line, and B104, an Iowa Stiff Stalk Synthetic line. The RI lines were topcrossed to the tester FR615 x FR697. The 143 topcrosses were scored for Southern rust in four environments. Time to flowering was measured in two environments. The RI lines were genotyped at 113 simple sequence repeat markers and quantitative trait loci (QTL) were mapped for both traits. The entry mean heritability estimate for Southern rust resistance was 0.93. A multiple interval mapping model, including four QTL, accounted for 88% of the variation among average disease ratings. A major QTL located on the short arm of chromosome 10, explained 83% of the phenotypic variation, with the NC300 allele carrying the resistance. Significant (P < 0.001), but relatively minor, topcross-by-environment interaction occurred for Southern rust, and resulted from the interaction of the major QTL with the environment. Maturity and Southern rust rating were slightly correlated, but QTL for the two traits did not co-localize. Resistance was simply inherited in this population and the major QTL is likely a dominant resistant gene that is independent of plant maturity.
Assuntos
Basidiomycota , Mapeamento Cromossômico , Meio Ambiente , Imunidade Inata/genética , Doenças das Plantas/microbiologia , Locos de Características Quantitativas , Zea mays , Cruzamentos Genéticos , Repetições de Microssatélites/genética , Doenças das Plantas/genética , Clima TropicalRESUMO
The records of 91 patients with vesicovaginal fistulas at the Ochsner Clinic between 1942 and 1974 were reviewed. The fistulas were managed in several ways: spontaneous closure, palliative operation, urinary diversion, transvesical repair, transvaginal repair, and a combined transvaginal-transvesical procedure. The latter had a 100% success rate in the eight patients in whom it was used. The technic of this procedure is described and the indications are expanded to include (1) large fistulas, (2) fistulas near the ureteral orifice, (3) if other abdominal or urologic surgery is being done, (4) if transvesical approach is being used, (5) previous failed attempts at correction, (6) difficulty of access by vaginal approach, and (7) fistulas resulting from transurethral resection of the bladder neck.
Assuntos
Fístula Vesicovaginal/cirurgia , Adolescente , Adulto , Feminino , Humanos , Métodos , Pessoa de Meia-Idade , Fístula Vesicovaginal/diagnóstico , Fístula Vesicovaginal/etiologiaRESUMO
Since 1947, carcinoma of the cervix uteri, Stage I, has been treated at the Ochsner Clinic with intracavitary irradiation and a radical hysterectomy--Wertheim type--and pelvic node dissection. If metastasis to the lymph node is demonstrated, external irradiation is administered postoperatively. Carcinoma of the cervix uteri, Stage II, has been treated with intracavitary radium and external radiation, followed by the same surgical procedure. All patients were treated surgically, except those with medical conditions precluding extensive operation. Five and ten year survival rates for Stage I cancer were 81.5 and 68.7 per cent, respectively; for Stage II, these rates were 64.5 per cent and 54.0 per cent, respectively. There were moderate complications from the combined therapy, with a ureteral fistula rate of 1.9 per cent. Although the combined use of irradiation and operation for carcinoma of the cervix uteri has been looked upon in this country with disfavor because of poor healing and complications, we have not found this to be so. With improvement of both radiation therapy and surgical management, these patients can be offered treatment based upon sound physiologic principles and can live in freedom from fear of recurrence in later years. The outlook is good for continued improvement in the complication rate, surgical technique and possibly, chemotherapy.