![Page 1: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/1.jpg)
![Page 2: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/2.jpg)
G. Mendel Hereditary factors
W.Johannsen,
1909
The gene – hereditary unit located in
chromosomes
G.W.Beadle,
E.L.Tatum, 1945Hypotheses “One gene – one enzyme”
Ingram, 1957Hypotheses “One gene – onepolypeptide”
Actual conceptsThe gene – a sequence of DNA resopnsable
for synthesis of macromolecules
Evolution of knowledge about geneEvolution of knowledge about gene
![Page 3: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/3.jpg)
DNA Double stranded molecule;
Polynucleotide chains;
Contains information about RNAs and proteins.
![Page 4: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/4.jpg)
Genetic code - DNA:
Letters: A, G, C, T
Words (one codon one amino acid): AAG - lys
AGC - ser
GCA - ala
TTC – phe
TAG – stop
Phrases: 5' AAGAGCGCATTCTAG 3'
lys – ser – ala – phe – stop
![Page 5: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/5.jpg)
Gene expressionGene expression
DNA mRNA ProteinDNA mRNA Protein
55’’--ATTGCAATTGCAAAGATTACCATGTGATTACCATGT--3’ 3’ Coding strandCoding strand ((untranscribeduntranscribed))
3’3’--TAACGTTCTAATGGTACATAACGTTCTAATGGTACA--5’ 5’ Template strandTemplate strand ((transcribedtranscribed))
Transcription (RNA polymerase)
55’’--AUUAUUGCAGCAAAGAGAUUAUUACCACCAUGUUGU--3’3’ mRNAmRNA
Translation (tRNA, ribosomes)
Leu Leu –– Ala Ala –– Arg Arg –– Leu Leu –– Pro Pro –– Cys polypeptideCys polypeptide
![Page 6: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/6.jpg)
![Page 7: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/7.jpg)
Definition:Gene – a fragment of polynucleotide chain
of DNA which contains information about
synthesis of:
one polypeptide or
some polypeptides or
a functional RNA (rRNA, tRNA, snRNA)
![Page 8: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/8.jpg)
Gene expressionGene expression
DNADNA
rRNArRNA
tRNAtRNA
mRNAmRNA ProteinProtein
![Page 9: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/9.jpg)
Classification:
Ist class genes – encode 5,8S, 18S and 28S rRNA;
IInd class genes = structural – encode mRNA
proteins;
IIIrd class genes – encode tRNA, 5S rRNA.
![Page 10: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/10.jpg)
Gene’s localization: Genes are located in DNA molecules;
Genes consist of unique or repeated sequences;
The genes from one molecule of DNA are separated
by non-coding sequences – spacers;
There are no morphological borders each gene has
only functional frontiers;
The length of genes is different.
![Page 11: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/11.jpg)
![Page 12: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/12.jpg)
![Page 13: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/13.jpg)
- The dimensions of human genome – 3,164 x 109 bp
- 2% of human genome encode for proteins
- Number of genes - 30000-40000
- Chromosome 1 contains – 2610 genes
- Chromosome Y contains – 255 genes
- Known function – 50% human studied genes
- Average length of gene – 3000 bp
- gene for β-globin – 1,5 kb
- gene for insulin – 1,7 kb
- gene for catalase – 34 kb
- gene for dystrophin - 2,4 Mb
![Page 14: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/14.jpg)
LengthLength, , kbkb %%
Up toUp to 1010 23,323,3
1010--2525 35,635,6
2525--5050 20,220,2
5151--100100 13,013,0
101101--500500 6,76,7
overover 500500 1,21,2
Distribution of human genes by lengthDistribution of human genes by length
![Page 15: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/15.jpg)
General structure of the gene
Central region – coding region;
Regulatory regions:
proximal – PROMOTER
distal – TERMINATOR
Modulation sequences
![Page 16: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/16.jpg)
Functions: At molecular level – control of polypeptide’s synthesis
functional protein
At cellular level – production of a normal cellular
structure, metabolic chain, signaling chain, etc.
At tissue level – realization of a specific function
(respiration, digestion, contraction, etc.)
At organism level – a specific trait (character)
![Page 17: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/17.jpg)
IInd class genes = structural(25% of nuclear DNA)
Encode one or some polypeptides;
Form monocistronic transcription units;
Have a mosaic structure (exon/intron);
May be transcribed: In all cells (house keeping genes)
Specific, depending on type of cell, age, factors;
Are transcribed by RNA-polymerase II in a primary transcript – pro-mRNA;
Are numerous, usually unique and heterogeneous;
May form repetitive or non-repetitive families of genes;
Present individual polymorphisms.
![Page 18: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/18.jpg)
Each cell contains a complete set of genes Each cell contains a complete set of genes
(30(30--40000 40000 pairs of genes in all 46 molecules of DNApairs of genes in all 46 molecules of DNA) )
Expression Expression –– only only 10% 10% of all genesof all genes
Permanent Permanent
expressionexpression
rRNA genesrRNA genes
tRNA genestRNA genes
HHouse keepingouse keeping
genesgenes
TemporaryTemporaryexpressionexpression
depending ondepending on::
-- tissuetissue;;
-- ontogenetic ontogenetic periodperiod;;
-- cell cycle cell cycle periodperiod;;
-- environment environment factorsfactors
Absence of Absence of
expressionexpression
pseudogenespseudogenes
![Page 19: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/19.jpg)
Types of structural genes House keeping – genes that encode for
indispensable cell proteins, active in all cells, in all
periods of life;
Tissue-specific – genes that encode for proteins
require for tissue specialization;
Regulatory of ontogenesis;
Dependent on environment factors.
![Page 20: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/20.jpg)
Gene families
Repetitive gene’s family: a family of identical genes
Non-repetitive gene’s family: a family of genes of related structure and usually related function
![Page 21: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/21.jpg)
Peculiarities of IInd class genes structure
![Page 22: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/22.jpg)
-10-20-30-40 +1 +10 +20 +30
TAFs
TFIID
TFIIA
TFIIB
RNA-polymerase II
TFIIF
TFIIE
Initiation of transcription of IIInitiation of transcription of IIndnd class genesclass genes
![Page 23: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/23.jpg)
Regions of structural genes Promoter:
TATA box (-20, -30)
CAAT box (-70, - 100)
Tissue-specific boxes( - )
Coding region:
site +1, leader sequence
exon1/intron/exon2/intron/.../exonn
Terminator Site of polyadenilation
Enhancers and silencers
![Page 24: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/24.jpg)
Promoter of IInd class genes Controls the initiation of transcription:
Activation of gene;
Fixing of TF and RNA-polymerase II;
Identification of (+1) and transcribed strand;
Directing of RNA-polymerase II.
Is not transcribed;
In different genes promoters contain different
specific boxes;
Mutations in promoter may induce gene
inactivation.
![Page 25: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/25.jpg)
Conservative boxes in structure of Conservative boxes in structure of
eukaryotic promoterseukaryotic promoters
StructureStructure SequenceSequence PositionPositionLength of Length of
bound DNAbound DNA
Transcription Transcription
factorsfactors
TATATATA--boxbox TATAAAATATAAAA -- 3030 1010 pp..nn.. TBPTBP
CAATCAAT--boxbox GGCCAATCTGGCCAATCT -- 7575 2222 pp..nn.. CTF/NFCTF/NF11
GCGC--boxbox GGGCGGGGGCGG -- 9090 2020 pp..nn.. SPSP11
OctamerOctamer ATTTGCATATTTGCAT2020 pp..nn.. OctOct11,, OctOct22
![Page 26: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/26.jpg)
Structure of promoter in structural genes in eukaryotes
(IInd class genes)
Structure of promoter in structural genes in prokaryotes
![Page 27: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/27.jpg)
Interaction promoter-enhancer
![Page 28: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/28.jpg)
Exons Sequences of structural genes that encode
polypeptide sequences;
Are found in pro-mRNA and mRNA;
Are transcribed and translated;
Each exon encodes a region of protein;
During alternative splicing some exones may be
removed.
![Page 29: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/29.jpg)
Introns
Non-coding sequences of structural genes that
separate exons;
Are found in pro-mRNA but not in mRNA;
Are transcribed but not translated;
During splicing all introns are removed;
![Page 30: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/30.jpg)
![Page 31: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/31.jpg)
Structure of terminatorStructure of terminator
![Page 32: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/32.jpg)
Structure of transcription unit which contains rRNA
genes in eukaryotes (Ist class genes)
• Promoter (-45 ... +20)
• Gene 18S
• Gene 5,8S
• Gene 28S
• Terminator
n
![Page 33: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/33.jpg)
Structure of 5S rRNA genes
Organization of IIIrd class genes
•Promoter – A box (+ 55) and B box (+ 80)
•Genes for tRNA / rRNA 5S
•Terminator
n
![Page 34: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/34.jpg)
![Page 35: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/35.jpg)
Structure of operon in prokaryotes
![Page 36: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/36.jpg)
Human mitochondrial genom
![Page 37: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/37.jpg)
![Page 38: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/38.jpg)
Mobile genetic elements =
TRANSPOSONES
TypeType Main geneMain geneType of Type of
transpositiontranspositionExemplesExemples
DNA DNA
transposonestransposonesTransposaseTransposase
Transposition through Transposition through
excision or replicationexcision or replication
Tn (Tn (bacterialbacterial))
P (P (DrosophilaDrosophila))
Retrovirus like Retrovirus like
transposonestransposones
ReversRevers--
transcriptase transcriptase
(revertase)(revertase)
Transposition through Transposition through
RNA produced on the RNA produced on the
basis of promoters basis of promoters
located in located in LTRLTR
THETHE--1 (1 (humanhuman))
Tz (Tz (yeastyeast))
RetroRetro--
transposones transposones
ReversRevers--
transcriptase transcriptase
(revertase)(revertase)
Transposition through Transposition through
RNA produced on the RNA produced on the
basis of neighbor basis of neighbor
promoters promoters
L1 L1 -- LINEsLINEs
![Page 39: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/39.jpg)
Biological role of transposones
Site-specific recombination
Individual polymorphism of DNA
Insertional mutagenesis
Genome instability fragile sites in DNA
Evolution of genomes
![Page 40: DNA - bimogeum.ucoz.com · G. Mendel Hereditary factors W.Johannsen, 1909 The gene – hereditary unit located in chromosomes G.W.Beadle, E.L.Tatum, 1945 Hypotheses “One gene –one](https://reader033.vdocuments.us/reader033/viewer/2022041723/5e4ffd4a842af511db30baf6/html5/thumbnails/40.jpg)
Medical importance of transposones
Changes in structure / function of structural genes
genetic diseases (hemophilia B, epilepsy, retinita
pigmentosum, etc)
Variability of pathogen agents resistance against
antibiotics and immune system