专业英语遗传学的基础.pptVIP

Anorganism/thatinherits/identicalallelesforatrait/fromeachparent/issaidtobehomozygous/[h?m?zaig?s]forthattrait;ifdifferentallelesforatrait/areinherited,theorganismisheterozygous[het?r?uzaig?s]forthattrait.从亲本遗传而来的是一个特征的两个相同的等位基因的个体被认为是纯合的。反之,遗传而来的是两个不同的等位基因的个体，就是杂合的。Whenanorganism/isheterozygous/foratrait,theresultingphenotype[fi:n?taip]/forthattrait/expressesonlythedominantallele.01对某一个特征而言,当个体是杂合时，它的表型仅由显性基因决定。020102Thus,theorganism’sphenotype-itsphysicalappearanceandproperties-/differsfrom/itsgenotype[d?en?taip],whichmayinclude/bothadominantandarecessiveallele./因此，生物的表型与基因型是不同的,表型是个体的物理特征和品质,而基因型包括一个显性基因和一个隐性基因。Apictorialrepresentationof/allpossiblecombinationofageneticcross/isknownasaPunnettsquare.

遗传杂交的所有可能的组合图表被称为旁纳特方格。Punnettsquare：amethodusedtodeterminetheprobabilitiesofcombinationinazygote[zaig?ut].Theresults/ofMendel’sexperiments/ondominantandrecessiveinheritance/ledto/Mendel’sfirstlaw:thelawofsegregation.01基于显性和隐性遗传的实验结果，孟德尔提出了分离定律。02Thislawstatesthat/foragiventrait/anorganism/inherits/oneallele/fromeachparent.该定律认为:对一个给定的特征而言,个体从每个亲本获得一个等位基因。Togetherthesealleles/form/theallelepair.这些等位基因一起形成等位基因对。Whengametes[g?mi:t]areformed/duringmeiosis,thetwoalleles/becomeseparated(halvingofchromosomenumber).减数分裂期形成配子时两个等位基因分离(染色体数目的减半)。Togainevidenceforhistheory/Mendelperformedtestcrosses,matingplants/ofunknowngenotype/toplants/thatwerehomozygous[h?m?zaig?us]recessive[risesiv]/forthetraitofinterest.为验证此理论，他做了测交实验，即基因型未知的植物个体与纯合隐性的个体杂交。Testcross：acrossbetweenaheterozygoteofunknowngenotypeandanindividualhomozygousfortherecessivegenesinquestion.Lessonfour

Foundationofgenetics

遗传学的基础

湖北医药学院附属人民医院生殖医学中心江胜芳（）孟德尔生平介绍孟德尔，GregorJohannMendel（），出生于奥地利西里西亚海因策道夫村一个贫寒的农民家庭，父母都是园艺家圣托马斯修道院修道士，现代遗传学之父毕业院校：奥尔米茨大学、维也纳大学主要成就：发现遗传定律背景知识