METHODS FOR DETECTION AND ESTIMATION OF LINKAGE BETWEEN A MARKER LOCUS AND QUANTITATIVE TRAIT LOCI Ⅰ. USING F_2 FAMILY SUBPOPULATION

Several methods heve been proposed over the years to detect linkage between a marker gene and a quantitative trait locus (QTL). Use of isozymes and restriction fragment length polymorphisms (RFLPs) as genetic markers has encouraged the development of new methods to detect linkage. In the paper authors present three methods to detect linkage and two methods to measure recombination frequency (r). The three methods that detect linkage are fit for the test of one or several QTLs of quantitative trait considered as long as the net gene effect vaIue of all loci belonging to a linkage cluster is greater significantly than zero, irrespective of their linkage relationship among the several QTLs.     

F9-1胚胎癌细胞与大鼠胸腺细胞杂交产生分化细胞

利用抗8氮鸟嘌呤的F9-1 aza突变株细胞与大鼠胸腺细胞融合,在HAT培养基中成功地筛选到FRT杂交细胞。该种细胞与亲本细胞F9-1 aza的细胞形态完全不同,呈成纤维样、上皮样、圆形或多突起样的分化细胞形态。在扩大繁殖后主要为成纤维样或上皮样细胞。对其中一个集落FRT-1核型检查表明杂种细胞染色体众数为80(范围62—88),C分带显示??包含F9和大鼠胸腺细胞二个亲本的染色体。FRT-1细胞的乳酸脱氢酶图谱中出现由大鼠LDH-A亚基与小鼠LDH-A亚基组成的杂种酶带。该细胞接种到经x光照射的129/Sv-ter小鼠皮下不能长瘤,亦不能在软琼脂上生长,表明F9-1 aza细胞的恶性表型已受到大鼠胸腺细胞基因组的抑制。     

DISCOVERY OF A NEW ENANTIORNITHINE BIRD FROM THE EARLY CRETACEOUS OF LIAONING, CHINA

Thethirdspecimenisdescribedhereasanewgenusandspecies:Boluochiazhengi,andfurtherreferredtoEnantiornithesasatleastfourenantiornithinesyna-Ipom0rphiescanberecognizedinthisspecimen:(1)intercondy1arfossaoftibiota-rsusnarrow,medialcondyleoftibi0tarsuswithfairlyflatanteriormarginindistalview;(2)metatarsusIVreduced;(3)slenderlateralpr0cessofsternumwithexpa-ndeddistalend;and(4)presence0fapeculiardorsalpr0cess0npr0xima1ischium.Boluochiaisbe1ievedtobeanewenanti0rnithinebirdfr0mtheEar1yCretaceousofChina…     

LATE MESOZOIC FISH FAUNA FROM WESTERN LIAONING, CHINA

Thelycopteridsarecharacterizedbythefollowingcombinationoffeatures:na-salstube-like,andseparatedbymesethmoid;temporalfenestrapresentonposterola-teralregionofcranium;hyomandibularwithadistinctanteroventralprocess;ant-orbitalsemicircularinshape,4-5infraorbitalbones,nosupraorbital;innermarginofpectoralfinwithalargeunbranchedray;afullneuralspinepresentonfirstpreuralcentrum,nomorethanoneepural,6-7hypurals,3-5uroneurals;cycloidscaleswithfineconcentriccirculiandwithbasalradii.Amongthenominatedgenerawhi…     

A NEW CRICETID FROM THE LUFENG HOMINOID LOCALITY, LATE MIOCENE OF CHINA

CricetidaeRochebrune,l883KowalskiaFahlbusch,1969Kowalskiahanaesp.nov.(Figs.l-3iPl.I)EtymologyNamedinhonourtoProf.HanDefel1whoconductedtheexcava-tionatthesiteinl983andhasmadegreatcontributionstothestudyofthehomi-noidfauna-HolotypeLeftMl(V1o843;2.oOX1.35mm).ParatypesLayerl:6M1,7M2,2M3,l2m1,l2m2,6m3(Vlo844.l-45);Il:3Ml,2M2,2M3,9m1,l3m2,3m3(Vlo844.46-77);IlI:amandib1ewithm1-3(Vlo844.78);IV:adamagedmandiblewithml-3(Vlo844.79);V:l5M1,14M2,8M3,16ml,12m2,9m3(VlO844.8O-l53);VI:onedamage…     

GLOBAL ATTRACTIVITY IN A N-SPECIES COMPETITION DIFFERENCE SYSTEM

1．Introduction．TherehasbeenrecelltlyasteadyIncreaseIntheInterestondifferencesystems．Onecommonlyusedtechn［queIstoconsideracont［nuoustimemodelgovernedbyordinarydifferentialequationsandobtainadlscretlzatlonof＊thetlzatlonsamebyreplacingthetimeder孔vatlvebyanappropriatedifferencequotientasInthecaseofEuler’smethodforthenumericalsolutionoffirstorderordinarydifferentialequations．SuchaprocedurehasbeproposedfortheLotka－VolterraN－spedescompetitionsystemoftheformItisknownthat［Chen,1988,G…     

A Dynamical Model of Biological Population Under the Variation of Resource and Its Numerical Analysis

1IntroductionTheLogisticequationofpopulationgroanisaclassicalmodeld~bingthePOPulationdy~cs,itisconSiderasthefundamentalthaiofPOPulationd~cs(May,1974).Inthebeisticmodel,thegrowth~ourofpopulationdependsonthebiolodedspeCies'intrinsicrateofincreaseandthe~lugCapaCityofenvironxnent.Therearetwoqueshonswoadinvestigatingfabler.First,dasapopulationreachitSintrinsicrateonlywhenthePOPulatonsizeisequaltozero?hand,isthe~lugcapadtyofenvironmentaconStantwhichcanbedet~nedinadvance?Infact,anypopulationc…     

Fractals of Protein Backbone Structures

IIntroductionPYOt6lflgy8fTSCtslStfuCtLlf6Withgedffi6tTICMlf－Slffill8Yltyh8sberflStUdi6dfOTiT18flyy6grs,Includingproteinpolypeptldechainfractaldimensions（FD）andtheFDofproteinsurfacest。c－turell－7）．Inl％2,Havlinand匝n－Avraham〔8〕studiedthefractaldlmenslonalltyofcommonplymerchainsbasedonaself、a、idingwalks（SAW）medel,andpresentedamethedforcorn－pUt;。prpOfthepl、erCha;nStrUCtUr。,qu。t;一（1）～（2）．Allenet。l．（2）一putedp］teinFDbyandassumdfracta］inedelofpr…