1 / 27

BIOMETRICS

BIOMETRICS. Module Code: CA641 Week 11- Basic Definitions . Image: http :// whitni13.blogspot.ie/2013/03/dna-structure.html. Outline. A molecular biology primer The Cell The DNA The Central Dogma of molecular biology Genetic diseases example

ely
Download Presentation

BIOMETRICS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. BIOMETRICS Module Code: CA641 Week 11- Basic Definitions Image: http://whitni13.blogspot.ie/2013/03/dna-structure.html

  2. Outline • A molecular biology primer • The Cell • The DNA • The Central Dogma of molecular biology • Genetic diseases example Acknowledgement: this presentation was created following Prof. LiviuCiortuz, “Computer Science” Faculty, “Al. I. Cuza” University, Iasi, Romania: http://profs.info.uaic.ro/~ciortuz/

  3. A Molecular Biology Primer- The Cell • The cellis the basic structural and functional unit of all known living organisms. • Instead of having brains, cells make decisions trough complex networks of chemical networks called pathways: • synthesize new materials • break other materials down for spare parts • signal to eat, replicate or die • Two different types of cells/organisms: Prokariotesand Eukariotes. Image: http://www.clipart.dk.co.uk/371/az/Human_body/Cell

  4. Life depends on 3 critical molecules • Nucleobases: cytosine (C), guanine (G), adenine (A), thymine (T)/ uracil (U) • DNA : made of A, C, G, T • Hold information on how a cell a cell works • RNA :made of A, C, G, U • provide templates to synthesize amino-acids into proteins • transfer short pieces of information to different parts of the cell • Protein : made of (20) amino acids (AA) • form enzymes that send signals to other cells and regulate gene activity • form body’s major components (e.g. hair, skin, etc.)

  5. DNA Structure Discovered in 1952 – by James Watson (biologist), and Francis Crick, (physicist, PhD std.) - Nobel Prize Image:http://www.biologycorner.com/bio1/DNA.html

  6. Some basic terminology • Chromosome : an organized structure of DNA in cell • in humans, 23 pairs • Locus: specific position on a chromosome (where a base pair is present) • Genetic map: orderedset of lociplus the information they contain • Chromatin: mass of genetic material that condenses to form chromosomes Image: http://www.accessexcellence.org/RC/VL/GG/human.php

  7. Basic terminology contd.’ • Genome: all genetic material • Gene: substring of DNA that encodes for a specific protein, length measured in base-pairs • contains introns(non-coding) and exons(coding) • Alleles: some nucleotides may differ in different individuals • Example: 18bp TACAagTACAaattGATT ATGTtcATGTttaaCTAA Image: http://en.wikipedia.org/wiki/Gene

  8. DNA Replication Image: The double helix of DNA unwinds and each side serves as a pattern to make a new molecule. Image courtesy U.S. Department of Energy Human Genome Program

  9. The Central Dogma of Molecular Biology DNA -> RNA -> Protein

  10. From DNA to RNA (transcription) • RNA • made of A , C, G, U. A-U, C-G • obtained from DNA sequence • Example: Step1: Nuclear RNA • TACAagTACAaattGATT -> AUGUucAUGUuuaaCUAA Step2: mRNA(transcript) - discard introns -> AUGUAUGUCUAA • Some other types of RNA exist, that do not code for proteins, but have other roles (sRNA, microRNA)

  11. From mRNA to proteins (translation) • Protein : - 20 possible aminoacids (AA) • AAs are obtained by ‘reading’ the mRNA • Each codon(triplet of DNA nucleotides) corresponds to one of the 20 amino acids: • E.g. UUG -> L (Leucine) • Stopcodons: UAA, UAG, UGA • Startcodon: AUG • Example: • mRNA : AUG|UAU|GUC|UAA=> aminoacids: START(M-Methionine), Y(Tyrosine), V (Valine), STOP • Note: a change from UAU to UAA would transform Y into STOP, yielding the wrong protein (SNPs –single nucleotide polymorphism, alleles)

  12. Genetic code The redundancy in the table — one amino acid may be encoded by several different codons — is a kind of defence against mutations... Image: http://biology.kenyon.edu/courses/biol114/Chap05/Chapter05.html

  13. Protein - Example • DNA sequence => mRNA sequence => protein AA sequence =>protein 3D structure => function (algorithms to determine structure...) • Ex: Haemoglobin Subunit Alpha: MVLSPADKTN VKAAWGKVGA HAGEYGAEAL ERMFLSFPTT KTYFPHFDLS HGSAQVKGHG KKVADALTNA VAHVDDMPNA LSALSDLHAH KLRVDPVNFK LLSHCLLVTL AAHLPAEFTP AVHASLDKFL ASVSTVLTSKYR Function: • Expression levels oxygen- transport • mRNA – microarrays, RNA-seq • Protein - quantitative real time polymerase chain reaction (qPCR)

  14. Genetic alterations on DNA A mutation - a change of the nucleotide sequence of the genome of an organism, virus Image: http://kabupatenklaten.com/gene-mutation-base-pair-insertions-or-deletions-causes-mutation-disorders

  15. Genetic alterations on DNA contd.’ • An insertion(insertion mutation) - the addition of one or more nucleotide base pairs into a DNA sequence • A deletion(deletion mutation) - a genetic in which a part of a chromosome or a sequence of DNA is missing Image: http://www.ebpi-kits.com

  16. The Central Dogma of Molecular Biology DNA -> RNA -> Protein

  17. Protein synthesis • http://www.learnerstv.com/animation/biology/Proteinsynthesis.swf

  18. Examples of genetic diseasesThalassemia • Even a mistake of just one position can have a profound effect. • Here is a small but devastating mutation in the gene for haemoglobin, the protein which carries oxygen in the blood. • good gene: AACCAG • mutant gene: AACTAG • People with thalassemia make less haemoglobin and fewer circulating red blood cells than normal, which results in mild or severe anaemia. • Thalassemia can cause significant complications, (e.g. pneumonia, iron overload, bone deformities and cardiovascular illness)

  19. Cri du chat • A rare genetic disorder caused by a deletion (the length of which may vary) on chromosome 5. • Symptoms • Babies: small at birth, may have respiratory problems, heart defects, muscular or skeletal problems, hearing or sight problems, or poor muscle tone • Adults: may have a small head (microcephaly), an unusually round face, a small chin, widely set eyes, folds of skin over their eyes, and a small bridge of the nose. People with cri-du-chat usually have difficulty walking and talking correctly. They may have behaviour problems (such as hyperactivity or aggression), and severe mental retardation.

  20. Cancer • A broad group of various diseases, all involving unregulated cell growth • Inherited mutations: • in the genes BRCA1 and BRCA2=> with a more than 75% risk of breast cancer and ovarian cancer • in MET gene =>…=> hereditary papillary renal cancer. • in APC gene => …colon polyps…=> colon cancer. • in BRAF gene =>…melanomas and nevi, lung cancers, colorectal cancer • in TP53 gene =>… More than 50% of human tumours contain a mutation or deletion of the TP53 gene • …

  21. Alleles • Dominant - exhibited phenotype • Recessive - "hidden" phenotype Note: • This slide and the next 4 slides are taken from http://www.cancer.gov/cancertopics/understandingcancer/cancergenomics/AllPages

  22. Penetrance • Sometimes one person with a dominant allele will expressa trait, yet that same genotype in another person will remain silent. => differences in penetrance. • Classic Mendeliangenetics: if an individual carries a dominant allele, the trait will be expressed (genotype = phenotype). However, if all carriers of a certain dominant allele in a population do not express the trait (same genotypes/different phenotypes), the gene is said to have incomplete penetrance.

  23. Autosomal Dominant Inheritance • Most hereditary cancer syndromes are inherited in autosomal dominant fashion. • Dominant inheritance occurs when only one copy of an allele is required for a particular trait to be expressed (phenotype). In autosomal dominant inheritance, multiple generations express the traits, with no skipped generations (assuming complete penetrance).

  24. Inherited Cancer Syndromes

  25. Cancer Susceptibility • Inherit a predisposition to cancer, not cancer itself • Mutation carriers can inherit their predisposing genotypes, yet they do not develop cancer => a somatic mutationin a second allele is required for cancer to develop • Sporadiccancer cases in families with a hereditary cancer syndrome. => phenocopies(their phenotype is similar to that of the affected mutation carriers, but their genotype is different) • => genetic testing may determine if the cancer is hereditary or sporadicin nature.

  26. What you should know? • What is the “Central Dogma” of molecular biology? • What is the difference between transcription and translationof the DNA? • What is a codon? • How would you define a gene? • What is DNA sequencing? • What is the difference between an intron and an exon? • What are the positive results of DNA mutations?

  27. Contact • Irina Roznovăț iroznovat@computing.dcu.ie • These slides: http://www.computing.dcu.ie/~iroznovat/tutorials/2012_2013/tutorial_CA641.shtml

More Related