2022年TextAResearchersDetectVariationsinDNAThatUndelieSevenCommonDiseases

1、精選學(xué)習(xí)資料 - - - 歡迎下載researchers detect variations in dna that undelie seven common diseases1 applyinganewgenomic technique toa large group ofpatients、 researchers in britain have detected dna variations that underlie seven common diseases、 discovering unexpected links between them.2 the variations pinp

2、oint biological pathways underlying each of the diseases、and researchershope that as the pathways are analyzed、 new drugs and treatments will emerge.3 theseven common diseases are bipolardisorder、 coronary arterydisease、 crohns disease、 hypertension、 rheumatoid arthritis、 and type 1 and type 2 diabe

3、tes.4 unveilingthecomplexgeneticsofcommondiseases wasthe promised payoff of the $ 3 billion human genome project、 completed in 2003、 but progress was slow until the recent development of devices that in a single operation can read the dna sequence at up to 500、000 points across an individuals genome

4、. with the devices、 called chips、 researchers can compare large numbers of patients with healthy individuals、 looking forpoints ofdifferences intheirgenomes that may be associated with disease.5 the approach is known as whole genome association、 and studies ontype 2diabetes、 heart disease and breast

5、 cancer have been reported within the last few weeks. those and the new study、 which was financed精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載by the wellcome trust of london、 demonstrate the power and reliability of the whole genome association method、 which stands in contrast to the many uncorroborated claims of disease

6、 genes made previously.6 “it s now absolutely clear that this is a new dawn in the genetics ofcommon human diseases”、 said peter donnelly、 a statistical geneticist atoxford university who was chairman of the consortium of 50 institutions involved in the wellcome trust study.7 theconsortiumcompared 2

7、、000 patients witheach disease from across britainwith3、000 healthy individualsas controls、 halfof whomwereborninasingleweekin1958.the consortium sfindingsarepublished in todays nature、 along wth reports from two groups that largely confirm the consortiums genomic hits in independent patient groups

8、suffering from crahns disease and type 1 diabetes.8 theconsortiumdiscovered some 24variantsstronglylinkedto disease、 about half of which have been found already by other groups and half of which are new.9 among its most interesting findings is that genetic variants close to a gene known as ptpn2 are

9、 associated with both crohns disease and type 1 disabetes. the link may be that both are autoimmune diseases and that thegene helpsregulatetheimmunesystem. researchers hopethat analysis ofthe genes operations may produce a treatment forthe two diseases.精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載10 the consortium also f

10、ound a genetic variant on chromosome 7 that carries a high risk of rheumatoid arthritis for women、 but none for men. very few such variants are known in diseases common to both sexes、 dr. donnelly said.11 anne bowcock、 a geneticist at the washington university school of medicineinst. louis、 said the

11、 wellcome trust study was a “tourde forcethat established how large-scale studies should be conducted.12 marienierras、anofficialofthejuvenilediabetesresearch foundation、 whichsupported the companion study oftype 1 diabetes、 said the research was “a significantadvance that identifiesadditional pathwa

12、ys that need to be looked a”t.13 dr. kari stefansson、 chief executive of decode genetics、 an icelandic company that has dominated the search for common disease genes until the arrival of the whole genome association method、 said the wellcome trust study was “a large body of work、 done by very good p

13、eople”but that it “hadnt come up with any big discovery”.14 dr. stefansson said the study had been delayed because of problems with the affymetrix chip it used、 and would have had greater impact inthe fast-moving field if it had appeared several months earlier.15 in the course of screening for any g

14、eographically related genetic bias、 the wellcome trust study researchers discovered a southeast-to-northwest gradient across britain composed of 13 genes. the genes were probably精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載undernaturalselection inthepeople whobecame theislandsfirst inhabitants.16 one of the genes、 whicha

15、rose among europes firstcattle herders 5、000 years ago、 enables people todrinkmilkinadulthood、 an ability known as lactose tolerance. the other genes、 the researchersspeculate、 may confer resistance to former scourges like pellagra、 tuberculosis and leprosy.17 another possible source of statistical

16、bias relates to race. the wellcome trust cosortium asked their 17、000 subjects to identify their race、 then genetically tested them and excluded 153 people who had non-european ancestry. the procedure is necessary because whole genome association studies look for small differences between patients a

17、nd controls、 which can be confounded by the genetic differences between races.18 the ws findings apply to populations ofeuropean descent andneed tobe verifiedinother races. geneticists do notyet knowwhat proportion of the genetic variants associated with common disease will be found in all races、 bu

18、t hope the overall biology will be much the same.19 “thegenetics gives us a whole new footholdintothe biologyofdisease”、 dr. donnedlly said. “if you find a variant in one population youmight learn a lotabout that disease which is relevant to the disease in other populations.”精品學(xué)習(xí)資料精選學(xué)習(xí)資料 - - - 歡迎下載20 because whole genome assaciation studies wor