医学遗传学-染色体分组、核型与显带

医学遗传学——染色体分组、核型与显带110页一、染色体分组(Chromosome

grouping)1-22号常染色体和X、Y性染色体形成24个基因连锁群(linkage

group)组染色体号大小着丝粒位置次缢痕随体说明A1-3最大1、3中2亚中1号长臂B4-5次大亚中C6-12X中等亚中9号长臂女16条男15条D13—15中等近端短臂末端E16—18小16中17、18亚中16号长臂F19—20次小中G21—22Y最小近端21号22号短臂末端女4条男5条女性：46，XX男性：46，XY二、染色体非显带核型（The

karyotype

of

non-banding

chromosome）非显带核型分析(karyotype

analysis)三、染色体显带(chromosome

banding)Q显带(Q

banding)G显带(G

banding)R显带(R

banding)T显带(T

banding)C显带(C

banding)N显带(N

banding)高分辩显带染色体(highresolution

banding

chromosome，HRBC)显带后的染色体呈现出独特的带纹即染色体带型(banding

pattern)荧光染料氮芥喹吖因(quinacrine

mustard，QM)显带Q带(Q

banding)反带(reverse

band)盐溶液处理，Giemsa染色，显示的带与G带相反R带(R

banding)T带(T

banding)加热，Giemsa染色，端粒特异性深染端粒(telomere)含有TTAGGG重复序列C带(C

banding)NaOH碱处理再Giemsa染色，使着丝粒和1、9、16号次缢痕以及Y染色体长臂远端的2/3的区段显带N带(N

banding

pattern)AgNO3染色可使核仁组织区(NOR)银染(Ag-NOR)受染的是与rDNA转录有关的一种酸性蛋白染色体的成份是核酸（DNA和RNA）和蛋白质（组蛋白和非组蛋白）。染色体经胰蛋白酶处理后，蛋白质因被水解而使DNA分子中的碱基暴露，由于碱基中G/C和A/T的比例不同，对染料结合的程度不一样

A/T碱基成份多，则Giemsa染料易与它结合而深染

G/C碱基成份多，则Giemsa染料不易与其结合而浅染。染色体纵轴上呈现明暗相间或深浅不一的带纹技术原理G带(G

banding)Chromosome

specimens

are

dealed

with

alkali

andTrypsase(parenzyme),

and

then

stained

by

Giemsa,

we

canobserve

the

alternate

with

bands

of

deep

color

and

light

c

under

the

microscope.A一秃头来二蛇腰三似蝴蝶翩翩飘B四像鞭炮五黑腰C六号ｐ似小白脸C七盖八下九细腰七(短臂远端处深染)八(着丝粒下部深染)九(着丝粒下部浅染)C十号ｑ臂三深带十一宽来十二窄十一(长臂近中段浅带宽)十二(长臂近中段浅带窄)C

X深带一担挑D十三下来十四中

十五深染头上瞧十三下(下部深染)十四中(中部深染)十五上(上部深染)E十六深带连着点十七长臂带脚镣十八人黑肚皮白F十九中间一点黑二十头重脚轻飘G二十一似三角形二十二似羽毛球老Y貌似宝葫芦四、人类染色体命名国际体制人类细胞遗传学命名的国际体制An

International

System

for

HumanCytogeneticsNomenclature,

ISCN㈠界标(landmark)、区(region)、带(bandLandmark：it

is

stable

andObvious(remarkable)

morphologicalcharacteristicson

chromosome.

Including：⑴the

end

of

two

arms,⑵centromere,⑶boundary

between

the

regions.Question：How

to

understand

that

thelandmark

band

is

the

first

band

of

the

nextregion？Region：the

region

between

the

twoadjacent(neighboring)

landmarks.

Thenomenclature

of

regions

begin

fromcentromere,

the

first

region

is

the

closestcentromere,

then

the

follows

are

named

thesecond

region,

the

third

region,

the

fourthregion

in

turn…Band：Chromosome

band

is

continuousand

without

non-band

areas.

Thenomenclature

of

band

also

begins

fromcentromere,

It

is

the

first

band,

the

secondband,

the

third

band,

the

fourth

band,

thefifth

band,

the

sixth

band

in

turn.

namedjust

like

region.㈡命名(Nomenclature)When

marking(indication)

a

band,

we

need

to

indicate

inturn(no

need

spacing

or

adding

punctuation):

①number

ofchromosome.

②number

of

arm.

③number

of

region.

④numbeof

band.For

example,1p35means

band

5,

region

3

of

short

arm

of

chromosome

114q32means

band

2,

region

3

of

long

arm

of

chromosome

141p31

1号染色体短臂3区1带1q421号染色体长臂4区2带界标是下一区的第一带㈢高分辨显带染色体High

resolution

banding

chromosome，HRBC一套单倍体染色体带纹仅

320条。染色体高分辨带型可显示550-850条带纹，有助于发现更细微的染色体结构异常1p31.1、1p31.2、1p31.3The

figure

shows

the

chromosome

1,

pleaseanswer

the

questions.⑴How

many

regions

are

theshort

arm

divided

into?

howmany

bands

does

each

regionscontain?⑵What

is

the

meaning

of

1q23?⑶According

to

the

rules

ofhuman

chromosomenomenclature,

write

the

bandname

of

the

short

arm

end.⑷

Label

1q32

on

the

figure

withan

arrows.⑵What

is

the

meaning

of

1q23?1q23

means

band

3,

region

2

of

longarm

of

chromosome

1.⑶According

to

the

rules

of

humanchromosome

nomenclature,

write

theband

name

of

the

short

arm

end.1p36⑷

Label

1q32

on

the

figure

with

anarrows.1q32⑴How

many

regions

are

the

short

arm

divided

into?

how

manybands

does

each

regions

contain?The

short

arm

of

No.1

are

divided

into

three

regions.the

first

region

has

three

bands.the

second

region

has

two

bands.the

third

region

has

six

bands.五、染色体的多态性(chromosomal

polymorphism)染色体的结构、带纹宽窄和着色强度等存在恒定的微小变异，染色体多态性主要在结构异染色质区，通常没有明显表型效应或病理学意义1、Y的