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Organisation of the genetic material in pro- and eukariotic cells. DNA, chromatin, chromosomes. 1 µ m = 2 Megadalton (2 x 10 6 Dalton) = 3 kbp. Intergenic DNA 2000 Mb. Genes and gene-related sequences 1200Mb. Genes 48 Mb. Related seq. 1152 Mb. Interspersed repeats 1400 Mb. - PowerPoint PPT Presentation
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Organisation of the genetic material in pro- and eukariotic cellsDNA, chromatin, chromosomes
1 m = 2 Megadalton (2 x 106 Dalton) = 3 kbp
Genome ContentHuman Genome3200 MbSINE: Alu, 281 bp, 300.000 p, 9%LINE: L1, 6500 bp, 50.000 p, 7%, retrotransposon
T phage ofEsherichia coli~ 50 m DNA.
Single Circular DNA molecule of Escherichia coli, ~1,4 mm long
~4 cm linear DNA molecule contains in a usual human chromosome
E. coli: 4 639 221 nukleotide pairs, 4200 genes
RelaxedSupercoiledTopoisomerases
Nucleus of a eukariotic cells (electronmicrograph)Function: protection, transport,gene expression
nuclear laminaHETEROCHROMATINeuchromatinheterochromatinnucleolus
1 m = 2 Megadalton (2 x 106 Dalton) = 3 kbp
Types of the chromatin: eu- and heterochromatin Structure of the chromatin ; histons, nucleosomes, solenoid and loops
Histones: small, basic, higly conserved proteins
30 nm chromatin fiber:interactions and modifications of site chains of histones and H1 histon are necessaryThe sructure of the 30 nmchromatin fiber is variable(heterogen)
11 and 30 nm chromatin fibers (electonmicrograph)beads-on-a-string structuresolenoid
H2AH2BH3H4
Chromatin structure and gene expresson in that area are hang on the chemical modification of histones (acetylations, metylation, phosphorylation)
A hiszton kd hipotzis
Condensins organise the loop-structureSMC = Structural Maintenance of Chromosomes family protein (part of the condensin complex)
DNAChromatinLoopsMetaphase chromosome
Chemical modification of the DNA (methylation) has role in regulation
de novo metylasesImprinting
XIST = X inactivaton specific transcriptXIC = X inactivation centerHistones also play role in the inactivation
Localization of the chromosome 18 and chr. 19 in interphase nucleus
The chromosome structure and the cell divisionArms, centromer, telomers
armssisterchromatidesKinetochor microtubuls
Lewin: Genes IX. Fig. 28.30
Telomer and telomerase
fibrillargranularlight stained
A magvacskafunkcii
Special chromosomesPoliten chromosome in salivary glands of Drosophila melanogaster Lampbrush chromosomes amphybian oocytes
Politenchromosomes
RNA synthesis on the politenchromosomes
Lampbrush chromosomes in an amphybian oocyte