人類染色體的正常核型

一、染色質(zhì)chromatin二、染色體chromosome三、人類染色體的正常核型

thenormalhumankaryotype

四、染色體的多態(tài)性

chromosomepolymorphism第二節(jié)遺傳的細(xì)胞基礎(chǔ)CellularBasisofInheritance(一)染色質(zhì)的分子結(jié)構(gòu)chromatinstructure(二)常染色質(zhì)和異染色質(zhì)

euchromatinandheterochromatin(三)性染色質(zhì)(sexchromatin)XchromatinYchromatinChromatin一、染色質(zhì)（1）?Chromatin一、染色質(zhì)（2）1Chemicalcomponentsofchromatin:DNA、protein、alittleofRNA2Higherlevelsofchromatinstructure:FourlevelsofDNApackingChromatin一、染色質(zhì)（3）30nmchromatinfiberofpackednucleosomes.SectionofchromosomeinanextendedformChromatid“Beads-on-a-string”formofchromatin.Higherlevelsofchromatinstructure:FourlevelsofDNApackingCellHistonesDNAChromatin一、染色質(zhì)（4）核小體/nucleosomeChromatin一、染色質(zhì)（5）

DNAnucleosomeChromatid×7×6×40×5×8400Chromatin一、染色質(zhì)（6）30nmchromatinfiberofpackednucleosomes.Sectionofchromosomeinanextendedform染色質(zhì)chromatin

Interphase。染色體chromosome

MphaseChromatin一、染色質(zhì)（7）常染色質(zhì)(heterochromatin)和異染色質(zhì)(euchromatin)

euchromatin:active,lesscompact。

Heteromatin:repressed,concentrated。heterochromatineuchromatinChromatin一、染色質(zhì)（8）

1949，BarrBarrbodyXbodyChromatin一、染色質(zhì)（9）X染色質(zhì)(Xchromatin)：female,interphase,1μmbody,heterochromatinChromatin一、染色質(zhì)（10）1961年，LyonX染色體失活假說(shuō)(Lyonhypothesis)：①onlyoneofthetwoX-chromosomesisgeneticallyactiveinfemalecells.TheinactiveXchromosomeissilencedbypackagingintotranscriptionallyinactiveheterochromatin

②ThechoiceofwhichXchromosomewillbeinactivatedisrandominplacentalmammalssuchasmiceandhumans,butonceanXchromosomeisinactivateditwillremaininactivethroughoutthelifetimeofthecell.?Chromatin一、染色質(zhì)（11）Dosagecompensationeffect劑量補(bǔ)償效應(yīng)

Y染色質(zhì)(Ychromatin)：maleinterphase

0.3μmbody,Q-brightregionofYchromosomeChromatin一、染色質(zhì)（12）structure;:短臂p長(zhǎng)臂q 著絲粒

centromere

主縊痕primaryconstriction端粒telomere次縊痕secondaryconstriction隨體satellite二、染色體(1)ChromosomeStructure,typeandnumberType二、染色體(2)ChromosomeMetacentricchromosome:1/2-5/8Submetacentricchromosome:5/8–7/8Acrocentricchromosome:7/8-telomere(一)非顯帶核型Karyotypewithoutband核型karyotype

核型分析karyotypeanalysis三、人類染色體的正常核型（1）Thenormalhumankaryotype

typemethodsGbandingtrypsin,Giemsa

QbandingquinacrinemustardQMRbandingNaCl,GiemsaTbandingHeat,GiemsaCbandingNaOH,GiemsaNbandingAgNO3三、人類染色體的正常核型（2）Thenormalhumankaryotype

QbandingGbandingModelofG-andR-banding染色體顯帶

Q-;G-;R-;C-;三、人類染色體的正常核型（3）Thenormalhumankaryotype

界標(biāo)landmark區(qū)region帶band

1p35高分辨顯帶Highresolutionbanding三、人類染色體的正常核型（4）Thenormalhumankaryotype

karyotypewithband三、人類染色體的正常核型（5）Thenormalhumankaryotype

三、人類染色體的正常核型（6）Thenormalhumankaryotype

Numberandstructure男性染色體

46,XY女性染色體46，XX四、染色體的多態(tài)性（1）chromosomepolymorphismFISHX染色體Y染色體13號(hào)染色體18號(hào)染色體21號(hào)染色體四、染色體的多態(tài)性（2）chromosomepolymorphism四、染色體的多態(tài)性（3）Detectionoftumor人類細(xì)胞遺傳學(xué)國(guó)際命名體制(ISCN,1995)(AnInternationalSystemforHumanCytogeneticNomenclature)p—短臂

q—長(zhǎng)臂del—缺失

dup—重復(fù)i—等臂

inv—倒位rob—羅氏易位

t—易位der—衍生染色體

ter—末端

46,XX,t(1;2)(p21;q23)染色體總數(shù)，性染色體組成，染色體變化染色體號(hào)；臂號(hào)；區(qū)號(hào)；