人類染色體核型分析. 核型分析 染色體型態 chromosome morphology 染色體異常...
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人類染色體核型分析
核型分析
染色體型態 Chromosome morphology 染色體異常 Chromosome abnormal 核型分析 Karyotype analysis
染色體的組成
Chromatin 染色質 Chromatin is the DNA-containing substa
nce extractable from eukaryotic nuclei Chromatin is NOT a macromolecule, thu
s has no fixed composition
染色質的特性 染色反應
– Isopyconosis – without differentiation– Heteropyconosis – with differentiation
• Positively (tightly coiled) v.s. negative (loosely coiled)
Euchromatin v.s. Heterochromatin– Euchromatin
• loose structure genetically active
– Heterochromatin• Compact structure genetically silent
Heterochromatin– Constitutive v.s. facultative
Chromomere 染色粒
Compact form of nucleosome Nucleosome
– Basic structure unit of chromosome
Nucleosome structure
Supercoiled
Linear differentiation
Different degree of coiling Telomere Centromere Chromomere Nucleolar organizer
Telomere
Telomere
Centromere
Kinetochore Spindle fiber attachment First constriction
Chromosome type
Metacentric Submetacentric Acrocentric Telocentric
Nucleolar organizer 核仁
Secondary constriction The collecting point of nucleolar materia
l nucleolus Produce 18s and 28s rRNA
Tomato telomere
Grasshopper telomere
Vicia faba chromosome
Rye chromomere
Zea mays Nucleolar organizer
Change in chromosome morphology
Chromosome break apart Reunion Ununited exchanged
Exchange Chromosome arm rearrangement
Translocation Between the arms of
different chromosomes
Translocation Centric fusion
Chromosome number variation
Euploidy Aneuploidy
Euploidytype symbol Set of chromosome
monoploid n ABC
Diploid 2n AABBCC
Polyploid
Triploid 3n AAABBBCCC
Tetraploid 4n AAAABBBBCCCC
Pentaploid 5n AAAAABBBBBCCCCC
Euploidy
Allopolyploidy– Sets of chromosome came from different s
pecies Autopolyploidy
– Sets of chromosome came from same species
Species A2n=AA
Species B2n=BB
Species C2n=CC
Autotriploid3n=AAA
Autotetraploid4n=AAAA
Autohexaploid6n=AAAAAA
Autopetaploid5n=AAAAA
F1
2n=AB
Allotetraploid4n=AABB
Triploid3n=ABB
Autoallohexaploid6n=AABBBB
Autoallooctaploid8n=AAAABBBB
Triploid3n=ABC
Allohexaploid6n=AABBCC
Aneuploidtype symbol Number of chromosome
Disomic 2n AABBCC
monosomic 2n-1 AABBC
Nullisomic 2n-2 AABB
Polysomic
Trisomic 2n+1 AABBCCC
Double trisomic 2n+1+1 AABBBCCC
Tetrasomic 2n+2 AABBCCCC
Pentasomic 2n+3 AABBCCCCC
Human chromosome
Chromosome number 46– Male 44 + XY– Female 44+ XX
1956 Tjio & Levan– Q-banding: fluorescence– C-Banding: Giemsa stain– G-Banding– R-Banding
Human and rat karyotypes
Rules for arranging chromosome
From Long to short If same in length
– Metacentric chromosome– Submetacentric chromosome– Acrocentric chromosome– Telocentric chromosome
Karyotype analysis1. Get a photo of chromosomes2. Cut off each chromosome3. Pairing the homologous chromosome4. Draw a base line in a piece of paper5. Arrange the chromosome according to the
rules shown in previous page6. Measure each arms of the chromosome pair7. Calculate the fraction of each arm in the
total arms’ length8. Get the short/long arm ratio for each pair of
chromosome9. Do a statistics for at least 30 photos