高中生物-Sex-and-inheritance-伴性遗传课件

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1、Chapter 7 Sex and inheritance 第七章第七章性性别和和遗传7.1Sexdetermination性性别决定决定7.2Sex-linkedinheritance伴性伴性遗传Sexchromosome性染色体性染色体Autosomes常染色体常染色体Primarysexualcharacteristics第一性征第一性征Secondarysexualcharacteristics第二性征第二性征Incubate孵化孵化Ovary卵巢卵巢Testis睾丸睾丸Hermaphrodite雌雄同体雌雄同体Homogametic同配型同配型Heterogametic异配型异配型T

2、estosterone睾睾酮Pseudoautosomalregion拟常染色体区常染色体区 7.1Sexdetermination(性性别决定决定):Primarysexdeterminationrelatestotheformationofovariesortestes.Thiscanberegulatedbygenesand/orenvironmentalfactors.Secondarysexualcharacteristicsarealsoundergeneticregulation.Inalligators(短吻短吻鳄)sexisdeterminedbythetemperature

3、atwhicheggsareincubated.Manyspecies(plantandinvertebrate)arehermaphrodite.sex-chromosomes：与性与性别决定明决定明显且直接相关的染色体且直接相关的染色体autosomes：与性与性别决定无明决定无明显直接相关的染色体直接相关的染色体Heterogametic:性染色体异型性染色体异型-体体细胞中性染色体的大小、胞中性染色体的大小、形形态、结构不同。构不同。如如X、Y染色体染色体性染色体异数：性染色体异数：体体细胞中性染色体数不同。胞中性染色体数不同。e.g.节肢肢动物蝗虫物蝗虫female2n=24(11A

4、)+XXmale2n=23(11A)+X07.1.1Sexchromosomesystems(性染色体系性染色体系统):Threedifferentsexchromosomesystemshavebeendescribed:XX-XOThisisfoundinmanyinsectspecies.maleXOfemaleXX蝗虫、椿象等蝗虫、椿象等 normalhumanmale22A+XYfemale22A+XXHumansexdeterminationanddifferentiationspermtype22A+X卵子卵子(22A+X;22A+Y)精子精子Y-maleXY-正常正常;XXY,

5、XXXY,XXXXY-异常异常男男XX-正常正常;XO-异常异常女女XX-XYThisisfoundinmammalsandincertaininsectsincludingDrosophila.SexdeterminationinDrosophila (果蝇中性别决定 XY型):ZW-ZZThisisfoundinbirds,snakes,wherethefemaleisZWandthemaleZZ.鸡、家蚕、家蚕、鸟类7.1.2染色体倍数型染色体倍数型(multipletype)性决定：性决定：雌蜂雌蜂2n=32；雄峰雄峰n=167.1.3 Environmentandsexdiffere

6、ntiation：1)nutrition：5d 蜂王浆蜂王浆 蜂王蜂王 受精卵受精卵 23d 工蜂工蜂(infertile)2)temperature：蝌蚪蝌蚪(XY)20 halfmaleandhalffemale 30 male,reversesexfromfemale 黄瓜、南瓜黄瓜、南瓜 葫芦科葫芦科 雌雄同株异花雌雄同株异花 富氮、短日照、富氮、短日照、低温有利分化雌花低温有利分化雌花Y染色体染色体-H-Y抗原基因抗原基因原始性腺原基原始性腺原基男性男性第一性征第一性征X染色体染色体-性激素受体基因性激素受体基因第二性征第二性征7.1.4H-Yantigenandsex性反转-母鸡司

7、晨 7.2Sex-linkedinheritance(伴性伴性遗传)7.2.1性性连锁Morganet al.foundin1910Morganchosered-eyedfemaleDrosophilamatewithwhite-eyedmale,F1generationhadredeyes.Ifusingwhitefemalematewithredmale,F1justhadthefemalewithredeyes.PF1White color is regulated by X linked recessive mutant gene carried by X chromosome,sta

8、ted as Xw X+X+XwY Allele X+Xw YF1 X+Xw X+Y 基因型1:1 全部红眼W基因传给雌性后代,不表现,仅携带.F2 X+Xw X+Y 互交 X+Y X+X+X+X+Y Xw X+Xw XwY 总表型 3 红:1白 雄性一半红,一半白;雌性全部红。When reverse cross happened:XwXw X+Y Allele Xw X+YF1 X+Xw XwY 基因型1:1 一半红一半白W基因传给雄性后代时性状表现F2 X+Xw XwY 互交 Xw Y X+X+Xw X+Y Xw Xw Xw XwY 总的表型 1 红:1白 均一半红,一半白。7.2.2芦

9、花芦花鸡的的毛色毛色遗传芦花雌芦花雌鸡(ZBW)非芦花雄非芦花雄鸡(ZbZb)F1芦花雄芦花雄鸡_非芦花母非芦花母鸡-非芦花雌非芦花雌鸡(ZbW)芦花雄芦花雄鸡(ZBZB)F1全部芦花全部芦花鸡-芦花芦花regulatedbyZlinkeddominantgeneBZ染色体染色体连锁显性性遗传正交中的正交中的F1互交得互交得F2？反交的反交的F1互交得互交得F2？7.2.3AusefulexampleiscolorblindnessinhumansThisisduetoarecessivealleleofagenewhichmapstotheXchromosome.Thenormalallel

10、eisdenotedBandthemutantalleleisb.AcolorblindmanmusthaveinheritedtheballelewithhisXchromosomefromhismother.IfshehadnormalvisionthenshemusthavebeenaheterozygoteBb.Acolorblindmancannottransmithisballeletohissonas,bydefinition,hissonmustinheritaYchromosomefromhisfather.Bythesamerulehemustpass btoallofhi

11、sdaughters.Anydaughterthatinheritstheb allelefromherfatherandanormalallelefromhermotherwillbeacarrierandtransmitthesyndrometo,onaverage,halfofhersons.Ifafemale-carriermarriedanormalman X+Xc X+Y X+Y X+X+X+X+Y 女儿正常 儿子一半色 Xc X+Xc XcY 盲，一半正常Afemale-carriermarriedamalecolorblindness X+Xc XcY X c Y X+X+X

12、c X+Y 女儿一半患病 儿子一 X c X c X c X cY 半患病7.2.4Hemophiliainhumans Hemophiliaisasexlinkedtraitinhumans,inheritedinthesamewaywithwhiteeyecolorinDrosophila.Malesarehemizygous,receivingtheironlyXchromosomefromtheirmother.Femalesarehomozygous,inheritingXchromosomesfrombothparents.Ifafemalehasadefectivegeneono

13、neofhertwoXchromosomes,shewillbeprotectedfromitseffectsbythenormalgeneonhersecondXchromosome.IfamalehasamutantXandanormalYchromosome,hewillbeaffectedbyaX-linkeddisease.Ason,whosemotherhastwonormalalleles,willnotbeaffectedbyhemophiliaevenifthefatherhasthediseaseandthedefectivegene.Adaughterofthesamep

14、arentswillbeaheterozygouscarrier.Aheterozygouscarriermotherandanormalfatherpassthegeneforhemophiliaontopossiblyone-halfoftheirchildren.Halfthedaughterswillbecarriersandhalfthesonswillbehemophilic.Therestofthesiblingswillbenormal.Daughters,aslongasoneofherparentsisgenotypicallynormal,canonlybecarrier

15、s.ThenormalgeneonthesecondXchromosomecounteractsthedefectandthedaughtersdonotsufferfromthetrait.Ifasonreceivesthedefectivegenefromhismother,hewillbehemophilicbecausetheYchromosomecannotcounteractthedefectivegenelocatedonhisXchromosome.Inthecaseofhemophilia,familyrecordsshowthatQueenVictoriahadamutan

16、talleleforhemophiliaandtransmittedthediseasetosomeofhersonsandmanyoftheEuropeanroyalhousesthroughmarriageofherdaughters.Asthereisnoevidenceofhemophiliainherancestors,QueenVictoriamusthaveinheritedamutationthataroseinthegermcellsofoneofherparents.Sex-linkedinheritance-性染色体上的基因所控制的性状与性性染色体上的基因所控制的性状与性

17、别相关相关联的的遗传现象象 RecessiveallelesofgenesmappingtotheXchromosomearenotexpressedinheterozygousfemalemammalsbutwillbeexpressedinmalebecausemaleshaveonlyoneXchromosome.Malestransmittherecessivealleletotheirdaughters,whereitisnotexpressed.Theyarereferredtoascarrierfemales.Thedaughters,inturn,transmitthealle

18、letohalfoftheirsons,whereitisre-expressed.伴性伴性遗传特点：特点：性状性状遗传与性与性别有关有关正、反交不一正、反交不一样出出现交叉交叉遗传现象象7.2.5Holandricinheritance-限雄限雄遗传SomegenesareontheYchromosomeandarepasseddirectlyfromfathertoson.Thisisknownasholandricinheritance.-基因在基因在Y染色体上且染色体上且仅在雄性个体中表在雄性个体中表现的的遗传方式方式Ageneforhairsontheouterrimoftheear

19、appearstoshowthispatternofholandricinheritance.Fathersonjustforman7.2.6Sexinfluencedinheritance-从性从性遗传 基因位于常染色体上，但在不同性基因位于常染色体上，但在不同性别个体中表型有差异。个体中表型有差异。e.g.绵羊有角羊有角 H 无角无角hfemalemaleHH有有有有Hh 无无有有 hh 无无无无可能可能H基因在基因在杂合合态时，它的性状表它的性状表现受性激素控制，受性激素控制，雌性激素抑制雌性激素抑制H的作用。的作用。AsmallregionofhomologyexistsbetweentheXandYchromosomes.Genesinthisregion,thepseudo-autosomalregion,donotshowsex-linkedinheritance.