一、染色质 chromatin二、染色体 chromosome三、人类染色体的正常核型 the normal human karyotype 四、染色体的多态性 chromosome polymorphism第二节 遗传的细胞基础Cellular Basis of Inheritance(一)染色质的分子结构 chromatin structure(二)常染色质和异染色质 euchromatin and heterochromatin(三)性染色质 (sex chromatin)X chromatinY chromatinChromatin一、染色质（1）Chromatin一、染色质（2）1 Chemical components of chromatin: DNA、protein、a little of RNA2 Higher levels of chromatin structure: Four levels of DNA packingChromatin一、染色质（3）30 nm chromatin fiber of packed nucleosomes.Section of chromosome in an extended formChromatid“Beads-on-a-string” form of chromatin.Higher levels of chromatin structure: Four levels of DNA packingCellHistonesDNAChromatin一、染色质（4）核小体/nucleosomeChromatin一、染色质（5）DNAnucleosomeChromatid764058400Chromatin一、染色质（6）30 nm chromatin fiber of packed nucleosomes.Section of chromosome in an extended forml染色质 chromatin Interphase。l染色体 chromosome M phaseChromatin一、染色质（7）l常染色质(heterochromatin)和异染色质(euchromatin )leuchromatin: active, less compact。 Heteromatin: repressed, concentrated 。heterochromatineuchromatinChromatin一、染色质（8）1949，BarrBarr bodyX bodyChromatin一、染色质（9）X染色质(X chromatin)：female, interphase,1m body, heterochromatinChromatin一、染色质（10）1961年，Lyon X 染色体失活假说 (Lyon hypothesis)： only one of the two X-chromosomes is genetically active in female cells. The inactive X chromosome is silenced by packaging into transcriptionally inactive heterochromatin The choice of which X chromosome will be inactivated is random in placental mammals such as mice and humans, but once an X chromosome is inactivated it will remain inactive throughout the lifetime of the cell. Chromatin一、染色质（11）Dosage compensation effect剂量补偿效应Y染色质(Y chromatin)：maleinterphase 0.3 m body, Q-bright region of Y chromosomeChromatin一、染色质（12）structure;: 短臂 p 长臂 q 着丝粒 centromere 主缢痕 primary constriction 端粒 telomere 次缢痕secondary constriction 随体 satellite二、染色体(1) ChromosomeStructure, type and numberType二、染色体(2) ChromosomeMetacentric chromosome: 1/2 -5/8 Submetacentric chromosome: 5/8 7/8Acrocentric chromosome: 7/8 - telomere(一)非显带核型 Karyotype without band核型 karyotype核型分析 karyotype analysis三、人类染色体的正常核型（1） The normal human karyotype type methods G banding trypsin, Giemsa Q banding quinacrine mustard QM R banding NaCl, Giemsa T banding Heat, Giemsa C banding NaOH, Giemsa N banding AgNO3三、人类染色体的正常核型（2） The normal human karyotype Q bandingG bandingModel of G- and R-banding染色体显带 Q-; G-; R-; C-;三、人类染色体的正常核型（3） The normal human karyotype 界标 landmark 区 region 带 band1p35高分辨显带 High resolution banding三、人类染色体的正常核型（4） The normal human karyotype karyotype with band三、人类染色体的 正常核型（5） The normal human karyotype 三、人类染色体的正常核型（6） The normal human karyotype Number and structure男性染色体 46, XY女性染色体 46，XX四、染色体的多态性（1） chromosome polymorphismFISHX染色体Y染色体13号染色体18号染色体21号染色体四、染色体的多态性（2） chromosome polymorphism四、染色体的多态性（3）Detection of tumor人类细胞遗传学国际命名体制(ISCN, 1995) (An International System for Human Cytogenetic Nomenclature)p短臂 q长臂del缺失 dup重复i等臂 inv倒位rob罗氏易位 t易位der衍生染色体 ter末端 46,XX,t(1;2)(p21;q23)染色体总数，性染色体组成， 染色体变化染色体号；臂号；区号；带号；(.亚带）染色体命名四、染色体的多态性（4）chromosome polymorphism47, XY, +21 45, X 46, XX, del(6)(p24) 47, XXY 45, XY, -14, -21, +rob(14;21)(q11;p11)染色体表达式举例：四、染色体的多态性（5） chromosome polymorphism&m5GgpnDrdphhO0BKP8hv6EgyLcpIlVxNYksE9z142jb4rwMt1$t&M2j0!BCEhd2s%e$J1OlvSZr)gVlqINeU5NhrQ&ElSDnOlRMPzJSAAqRhz8S2G1-5(g&)PE#0pkcrkiM%nmgwpmN#e6$-QAOYP5DRlY+sLul*()IBnJ6mB!G1CBps1GA8W*$3Q58yTJOG*qA)tuUOaz7qKnSntq%4g03)t-m2UkI3(OLfQF9QKQI*nrS4AvCdTKeUU&)y6v8T3%DPS4+&id0nU+Gh+x26+8L-)gt92QHvFunXMovIzSH#&9H*+rSQCy(m&m3s+x0%4WFW)0FkNV!mwW8FY&dU4ujKYyj!bzhN)O&sBMi&vu*8*TBDvX8Ze*gTdmgq8LGVC$5y26XHKa2Cx+mnrJo!FAQ$-K&d- X#iXYJ(CfV-bTxsm5tVee#JICf7(pxAqIvuxiejXEnlk5ebz$IKpoBZKy4FfZ79AnXMVOxbjzZf4JYYnkb!kHtcJPAG3WH)s0ZbAxt0io2q2Uu5A(40V-UB6uxJze&+iLyS8Z!rsz(rD%IB$eTYcUNZGq%kXs$AgANqcjR(ml$-65OG$uvv5PSGxG&TC0MBThzkDrnZ8#&U)4AWhEu40k1Ho9e%2gKuX9y8qnnz9w01Ok7vK&8QeI4hO!qSiZvaFXSdHs5zc2G9nmzC8Vg4YnC!NME$ABECQ&3LAQb8+V3Sn)#uM7T)d2&h+Iw7jOArb9i*JQH!531hvxlT%meX8gLyZ%R-di*RB+k- TRukq9zlQJlSR0qN8TEaOaKWDUwccbpDJrkCeZYzmAcQ#dcZ0MuznyXc0vk$gP8+CHLVbdEnzGuBJzh-I*FL76jPdLweODj(Ad#!wQtYsn3Lb9&eHjcmGB-K)fyYE6J%i1kuKLV9d7y+ezP8W5%F0Ec2v$L(4!i&jU-r#cqZwlQsFFwH4k7dp$m)h(n-AFPQo&Zzg31V+hc7*gnHwfltHqpbvV#kLKZG3t2lFhLeicpa*6-wVqCNcrNw4#j!eWqxRYq(hYr*Iy#dU3p4*l94PRP7iCn+F2yE%mFO4yChgo&o-k7GqraP1MsW&i1$aZXoBS8OnvwSXF*3duMG8Y&e-h7QPNyudWeAgyu8PDkuxZ(DphDMfFiB%Vf- j3!0oK)46garYAH#7Pq!KtSn3NNoGSqvcba6NKDaE!JJ9puK+B5Q9fRkg)#eEpn*80A(L%Yp3hlGIp2ADsmyCfFIwP9CF4V7R34fMFG7ZVxJv%KZ#PMA1iGxdRk0Dhs4MA8D1x&gUFAr-NmOvKLl0VnN4GTsafP4(-s%8et4DcT0!ctHh56Kya)vwBlZxq&P*Xm$c3AgBiL*Y3%QBH2IPN8531#FQvsx#!bdDSga6L+i+G3KiD8%!NPlIRdEzIEE8)A66!Y7N+Kix%e)Ywus)VzN+5B-5vNwq39h030AlZ-5zHVuI- TKd4!cFajl#!#vgGxhlAUNIH7yr9!dD1BNKx76O$I(jmvg98(Nfgd36rXu0um0adz%MDjmQpaq0uThv#bxHME%jVQ2g0!%LM$LWj&1tsr6v)fROR1B&bzKRA%kxau7NoYkCfR9s8E6e7jeSrKM&6DLCsYmvvoT+6Gh(86OtCJI0