1CURS OPTIONAL GENETICA MEDICALA SI BIOLOGIE MOLECULARA

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James Rothman- directorul departamentului de Biologie Celulara de la Yale (SUA), Randy Schekman -cercetator la Universitatea California, Berkeley (SUA) Thomas Sudhof profesor la Universitatea Stanford (SUA), 2013

Human Genome Project

Human Genome ProjectGoals: identify all the approximate 30,000 genes in human DNA, determine the sequences of the 3 billion chemical base pairs that make up human DNA, store this information in databases, improve tools for data analysis, transfer related technologies to the private sector, and address the ethical, legal, and social issues (ELSI) that may arise from the project. Milestones: 1990: Project initiated as joint effort of U.S. Department of Energy and the National Institutes of Health June 2000: Completion of a working draft of the entire human genome February 2001: Analyses of the working draft are published April 2003: HGP sequencing is completed and Project is declared finished two years ahead of scheduleU.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

What does the draft human genome sequence tell us?

By the Numbers The human genome contains 3 billion chemical nucleotide bases (A, C, T, and G). The average gene consists of 3000 bases, but sizes vary greatly, with the largest known human gene being dystrophin at 2.4 million bases. The total number of genes is estimated at around 30,000--much lower than previous estimates of 80,000 to 140,000. Almost all (99.9%) nucleotide bases are exactly the same in all people. The functions are unknown for over 50% of discovered genes.U.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

What does the draft human genome sequence tell us? The Wheat from the Chaff

Less than 2% of the genome codes for proteins. Repeated sequences that do not code for proteins ("junk DNA") make up at least 50% of the human genome. Repetitive sequences are thought to have no direct functions, but they shed light on chromosome structure and dynamics. Over time, these repeats reshape the genome by rearranging it, creating entirely new genes, and modifying and reshuffling existing genes. The human genome has a much greater portion (50%) of repeat sequences than the mustard weed (11%), the worm (7%), and the fly (3%).U.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

How does the human genome stack up?

Gene number, exact locations, and functions Gene regulation DNA sequence organization Chromosomal structure and organization Noncoding DNA types, amount, distribution, information content, and functions Coordination of gene expression, protein synthesis, and post-translational events Interaction of proteins in complex molecular machines Proteomes (total protein content and function) in organisms Correlation of SNPs (single-base DNA variations among individuals) with health and disease Disease-susceptibility prediction based on gene sequence variation Genes involved in complex traits and multigene diseases Developmental genetics, genomics Future Challenges: What We Still Dont KnowU.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

Anticipated Benefits of Genome ResearchMolecular Medicine improve diagnosis of disease detect genetic predispositions to disease create drugs based on molecular information use gene therapy and control systems as drugs design custom drugs (pharmacogenomics) based on individual genetic profiles Microbial Genomics rapidly detect and treat pathogens (disease-causing microbes) in clinical practice develop new energy sources (biofuels) monitor environments to detect pollutants protect citizenry from biological and chemical warfare clean up toxic waste safely and efficientlyU.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

Anticipated Benefits of Genome Research-cont.Risk Assessment evaluate the health risks faced by individuals who may be exposed to radiation (including low levels in industrial areas) and to cancer-causing chemicals and toxinsBioarchaeology, Anthropology, Evolution, and Human Migration study evolution through germline mutations in lineages study migration of different population groups based on maternal inheritance study mutations on the Y chromosome to trace lineage and migration of males compare breakpoints in the evolution of mutations with ages of populations and historical events U.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

Anticipated Benefits of Genome Research-cont.DNA Identification (Forensics) identify potential suspects whose DNA may match evidence left at crime scenes exonerate persons wrongly accused of crimes identify crime and catastrophe victims establish paternity and other family relationships identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers) detect bacteria and other organisms that may pollute air, water, soil, and food match organ donors with recipients in transplant programs authenticate consumables such as caviar and wineU.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

Medicine and the New GeneticsAnticipated Benefits: improved diagnosis of disease earlier detection of genetic predispositions to disease rational drug design gene therapy and control systems for drugs personalized, custom drugs U.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003Gene Testing Pharmacogenomics Gene Therapy

ELSI: Ethical, Legal, and Social Issues Privacy and confidentiality of genetic information. Fairness in the use of genetic information by insurers, employers, courts, schools, adoption agencies, and the military, among others. Psychological impact, stigmatization, and discrimination due to an individuals genetic differences. Reproductive issues including adequate and informed consent and use of genetic information in reproductive decision making. Clinical issues including the education of doctors and other health-service providers, people identified with genetic conditions, and the general public about capabilities, limitations, and social risks; and implementation of standards and qualitycontrol measures.U.S. Department of Energy Genome Programs, Genomics and Its Impact on Science and Society, 2003

HapMap Begun in 2002, the project is a 3-year effort to construct a map of the patterns of SNPs (single nucleotide polymorphisms) that occur across populations in Africa, Asia, and the United States. Consortium of researchers from six countries Researchers hope that dramatically decreasing the number of individual SNPs to be scanned will provide a shortcut for identifying the DNA regions associated with common complex diseases Map may also be useful in understanding how genetic variation contributes to responses in environmental factorsGWAS(genome wide association study) Agenome-wide association study(GWAS), also known aswhole genome association study(WGAS), is an examination of all or most of the genes (thegenome) of different individuals of a particular species to see how much the genes vary from individual to individual

Representative Genomewide Association Studies of Common Cardiovascular Diseases.O'Donnell CJ, Nabel EG. N Engl J Med 2011;365:2098-2109

GENOMICA / PROTEOMICA / METABOLOMICAGenomica studiaza genomul cu toate componentele structurale (acizi nucleici, proteine)

Cercetarea unei singure gene nu intra in cadrul definitiei genomicii, cu exceptia cazului in care scopul analizei acestei informatii genetice si functionale este de a elucida efectul si locul sau in cadrul intregii retele a genomului.

Biologia moleculara se ocupa cu intelegerea interactiunilor dintre diferite sisteme ale celulei (inclusiv interactiunile dintre ADN, ARN si biosinteza proteinelor) si deasemenea cu intelegerea modului in care aceste interactiuni sunt reglate.

MEDICINA GENOMICAMedicina genomic este o medicin individualizat, personalizat i predictiv, preventiv, proactiv (prospectiv) i participativ (regula celor 5 P).

ONCOGENOMICAMedicina genomica

ONCOGENETICAFiecare tumor conine un numr foarte mare de modificri genetice i epigenetice diverse.numai un numr mic de mutaii (mai puin de zece), numite mutaii conductoare (driver mutations) sunt necesare pentru iniierea clonei canceroase (mutaii oncogenice) i pentru meninerea/expansiunea tumoral (mutaii de meninere) unele mutaii conductoare au fost definite ca modificri acionabile (actionable aberrations), n sensul c implic aciuni practice deoarece au impact asupra managementului cancerului prin utilizarea lor n diagnostic, prognostic i/sau predicie; o parte dintre acestea sunt i tratabile(druggable aberrations) ntruct oncoproteinele codificate pot fi inta unor noi terapii, care schimb evoluia bolii

ONCOGENETICAInductia apoptozei prin letalitatea sinteticaAcest concept se bazeaz pe interaciunea genetic dintre dou sau mai multe gene sau ci moleculare;inhibarea lor combinat/concomitent produce eliminarea selectiv a clonelor de celule premaligne, fr efecte citostatice asupra celulelor normale i deci fr efecte toxice.

ONCOGENETICAAstfel, celulele canceroase dezvolt rezisten la apoptoz, prin activarea unor ci de supravieuire celular, secundar unor mutaii (de exemplu, a genei APC n cancerul colorectal sau a oncogenei KRAS n cancerul pulmonar fr celule mici);

celulele canceroase cu aceste mutaii pot fi eliminate prin folosirea unei combinaii sintetic-letale

ONCOGENETICAUn alt exemplu de letalitate sintetic este reprezentat de celulele canceroase cu mutaii ale genelor de reparare ale leziunilor ADN (de tipul BRCA1 i BRCA2 n cancerul ereditar de sn i ovar sau PTEN n cancerul de prostat).

Administrarea unor enzime implicate n repararea ADN, duce la cumularea efectelor (amplificarea rupturilor ADN) n celulele canceroase i moartea acestora) efect coroborat cu radioterapia.

Conceptul letalitii sintetice poate fi utilizat pentru o terapie personalizat n cancer, determinat de profilul individual oncogen

ONCOGENETICAleziunile genetice gsite n trunchiul principal (clona iniial) sunt exprimate i n ramurile sale (subclone).

n aceste condiii, se impune schimbarea strategiilor terapeutice i direcionarea lor spre gen i nu spre proteina codificat de gen, urmrind inhibiia ei funcional sau restaurarea structurii ei normale

PROTEOMICAProteomica se ocupa cu studiul la scara larga a structurii si functiei proteinelor.

Analiza de secven poate furniza mai multe date prin compararea secvenei unei proteine cu cele stocate n bazele de date. se pot gsi informaii despre: structura, interaciile, activitatea biochimic, evoluia i chiar rolul potenial ntr-o boal.

Structura tridimensional depinde de plierea catenei polipeptidice n spaiu care reflect:Lungimea secvenei (tip de aminoacizi i secven)Structura primar Modificri post translaionale suferite de aminoacizi

Proteinele cu secvene similare au proprieti similare. Paradigma secven similar/ funcie similar st la baza bioinformaticii i ne permite s se fac predicii structurale i funcionale pe baza secvenei proteice.

T E H N O L O G I A P C RReacia PCR (Polymerase Chain Reaction = Reacie de Polimerizare n Lan) este o metod de amplificare enzimatic in vitro a unei anumite secvene de ADN.tehnica PCR permite ca o singura copie a unei secvente de ADN sa fie copiata de milioane de ori sau chiar sa fie modificata pe parcursul amplificarii (atunci cand este dorit acest lucru: ex. Introducerea unei mutatii). Din punct de vedere chimic, reacia PCR este constituit din cicluri succesive de replicare ADN in vitro, folosind 2 primeri oligonucleotidici ce hibridizeaz cu cele 2 catene ale secvenei originale (folosit ca matri n replicare).

Diferena esenial ntre o asemenea reacie de replicare i un proces de replicare ADN in vivo, l reprezint faptul c n reacia PCR etapa de desfacere a dublului helix matri i, respectiv, cea de ataare a primerilor, nu sunt realizate enzimatic, ci prin parcurgerea unor trepte de temperatur, iar singura enzim folosit n reacie este o ADN polimeraz ADN-dependent (cu funcie de replicaz).

TIPURI DE PCRReal Time PCR (PCR cantitativ), Real Time PCR este o metoda diferita fata de RT-PCR (reverse transcriptase PCR). Real Time PCR este o metoda care include atat amplificarea fragmentului ADN in timp real cat si analiza acestuia.Se folosesc cantitati foarte mici de proba. Se pot amplifica atat probe ADN cat si probe ADNc cu aceeasi viteza si eficientaUn numar mult mai mare de probe de concentratii diferite pot fi analizate in acelasi timp.Amplificarea fragmentului ADN se poate vizualiza cu ajutorul moleculei reporter pe tot parcursul reactiei, nu la sfarsit.

Aplicatii Real-Time PCRReal-Time PCR poate fi utilizat pentru:Genotipare Trisomii si detectarea numarului de gene unice din genom Genotiparea microdeletiilor Haplotipare Analiza cantitativa a microsatelitilor Diagnosticul prenatal al celulelor fetale din sangele maternDiagnosticul cancerelor Cuantificarea expresiei genelorMasurarea expunerii la radiatii Studiul ADN mitocondrial Detectia metilarii Detectia inactivarii cromosomului X

Clonarea moleculara si Expresia genelor

Clonarea molecular se refer la procedura de izolare a unei anumite secvene ADN i obinerea mai multor copii ale acesteia in vitro. Clonarea este frecvent folosit pentru amplificarea secvenelor ADN ce conin gene, dar poate fi folosit i pentru amplificarea oricrei secvene ADN cum ar fi promotorii, secvene necodate i secvene aleatoare ale ADN. Enzimele de restrictie sunt o clasa speciala de enzime utilizate pentru a taia ADN-ul la un anumit site de restrictie pe care il recunosc, avand ca rezultat fragmente de ADN de lungimi predictibile. Utilizarea enzimelor de restrictie permite ca fragmente de ADN din surse diferite sa fie reconectate si astfel, prin ligarea lor, este obtinut ADN-ul recombinat.

Adesea asociat cu organismele modificate genetic, ADN-ul recombinat este utilizat in constructia vectorilor care au la baza plasmidele (fragmente scurte de ADN circular).

Clonarea moleculara si expresia genelorVectorii de expresie sunt un tip specializat de vectori de clonare in care semnalele pentru translatie si transcriptie necesare pentru controlul genei de interes sunt incluse in vectorul de clonare. Aceste semnale pot fi create artificial pentru a controla mai usor expresia genei de interes.

Expresia genelor este o tehnica de clonare ADN care utilizeaza vectori de clonare pentru a genera o biblioteca de clone, in care fiecare clona exprima o proteina. Biblioteca de expresie este analizata pentru identificarea clonei care intereseaza si aceasta este recuperata pentru investigatii ulterioare. Un exemplu ar fi izolarea unei gene care confera rezistenta la antibiotice.

Scop De obicei scopul final al expresiei genelor este a produce o anumita proteina in cantitate mare.

EXPRESIA GENELOR -APLICATIIObinerea insulinei umane.Noile tehnologii industriale de obinere a insulinei umane au fost posibile odat cu extragerea genei insulinei (W.Gillbert i colaboratorii si, 1980) i crearea moleculelor recombinate de ADN n baza plasmidelor

Moleculele recombinate de ADN sunt transferate n Escherichia coli, unde are loc realizarea informaiei genetice codificate n molecula de ADN. Paralel cu proteinele specifice bacteriei, se sintetizeaz i insulina. Pentru a proteja insulina uman n molecula recombinat de ADN se ncadreaz, pe lng gena insulinei, i o gen reglatoare care codific proteine specifice colibacililor (galactozidaza). Ca rezultat al manifestrii informaiei genetice a moleculei recombinate de ADN, se obine o caten polipeptidic hibrid, din care mai apoi se separ insulina.

se obin aproximativ 200 grame de insulin de pe 1 m3 de mediu de cultur (1600 kg de pancreas de bou sau porc.)

Obinerea somatotropinei.

Sinteza acestui hormon pe cale artificial s-a nceput cu producerea de ADNc cu ajutorul revers-transcriptazei, avnd ca matrice ARNm din hipofize (transcripie invers).

Acesta a fost clonat, apoi tiat cu enzime de restricie pentru obinerea secvenei nucleotidice corespunztoare somatotropinei, cu excepia fragmentului ce determin primii 23 de aminoacizi.

Fragmentul n cauz era clonat separat, ca rezultat al unei sinteze chimice, apoi cele dou segmente unite, la ele se adug segmente reglatoare i pe baza plasmidelor se obine plasmidiul recombinat cu gena HGH (a somatotropinei). Colibacilii, primind acest plasmid recombinat, sintetizau somatotropina (la 1 litru de mediu de cultur se obine 2,0-2,5 mg somatotropin).

EXPRESIA GENELOR- APLICATII

TELOCIT

Telocitele sunt celule cu corp mic, dar cu prelungiri extrem de lungi (asemanatoare prelungirilor neuronilor), prezente in aproape toate organele.

Rolul telocitelor este acela de tele-coordonare, la distanta, prin intermediul prelungirilor lor extrem de lungi si subtiri (telopode), a altor tipuri celulare, de stabilire de contacte de tip "sinapse stromale" cu acestea si de comunicare prin intermediul unor structuri microveziculare - exozomi Se folosesc in terapia regeneratoare post-infarct de miocard

NIGMS Image Gallery

Prima data termenul EPIGENETICA a fost utilizat pentru a explica trasaturi fenotipice care nu puteau fi justificate prin mecanisme genetice (Conrad Waddington 19051975)

Epigenetica promite sa descifreze procesele biologice implicate in dezvoltare si diferentiere, interfata dintre organisme si perturbarile induse de mediu (inclusiv carcinogeneza)

Epigenetica = ansamblul de mecanisme care moduleaza structura cromatinei si regleaza stabilitatea expresiei genice pentru definirea identitatii celulare

Desi majoritatea celulelor umane au aceeasi informatie genetica cuprinsa in ADN, organismul produce in cursul diferentierii diferite tipuri de celule;

Fiecare celula are profilul propriu de expresie genica si functii specifice.

Exista unui numar mare de studii care arata ca genetica (singura!) nu poate explica toate aspectele legate de dezvoltare si diferentiere

Importanta factorilor non-genetici sustinuta inclusiv de observatii la unele animale clonate, probabil si ca rezultat al expresiei incorecte in imprinting.

Informatia epigenetica determina modularea expresiei genice conform unui pattern determinat de etapa de dezvoltare, de tipul de tesut si de conditile ambientale determinind un anumit fenotip celular.

Replicarea cromatinei in cursul fazei S a ciclului celular ofera oportunitatea factorilor responsabili sa adauge si sa propage in noua catena ADN toti markerii epigenetici identificati in celula parentala.

Epigenetica a adus rezultate remarcabile in optimizarea strategiilor de diagnostic (diagnosticul timpuriu si preventia) si in elaborarea strategiilor terapeutice epigenetice.

EPIGENETICAPrimul mecanism epigenetic descris este inactivarea cromozomului X(teoria Mary Lyon/ metilare)

. 1. Metilarea ADN-Adaugarea covalenta a unei grupari metil (-CH3) in pozitia 5 a citozinei cu obtinerea 5-metil citozinei (5mC);

5mC reprezinta 1% din totalul bazelor azotate

Donor de grupari metil: S-adenozil metionina (SAM)

-Situsuri preferentiale de metilare: secvente CpG

Originea grupelor metil: dieta (metabolismul folatului sau metioninei, seleniu)

Nucleotidele CpGDistribuite in intreg genomulConcentrate in regiuni numite insule CpG (60% din ADN genomic)

Localizate preferential la nivelul: - promotorului genelor - regiunilor ADN reglatoare -ADN repetitiv (palindroame, ADN satelit)

clusterele CpG nemetilate sunt situate in genele implicate in desfasurarea optima a activitatii celulare (ex. gene housekeeping).

Pattern-ul de metilareConservat in celulele somaticeRealizat de ADN metiltransferaze (DNMT- DNA methyltransferases)DNMT1- actioneaza preferential asupra ADN hemi-metilat. -metileaza catenele nou sintetizate imediat dupa replicare, folosind matrita parentala.

ADN metiltransferaze de novo:- DNMT3A - DNMT3B

. Tumorigenic Mechanisms in Mammalian Cells. Both genetic and epigenetic aberrations are involved in neoplastic transformation. These 2 alternate pathways of tumorigenesis are linked by an intricate cross-talk and can, either individually or in synergy, lead to the development of the malignant phenotype

Metilarea aberanta ADN si cancerDefectele de metilare se pot transmite pe linie germinala- cancere familiale (colon, endometru)Metilarea genei p16 in leziuni neoplazice la fumatori(dg. In sputa cu sensibilitate 96%) pentru cancerul pulmonar lipsa imprinting Insulin like growth factor in neoplasmul colorectal (dg. materii fecale)

. Folate metabolism: folate, along with choline, methionine, cobalamin, pyridoxine, and riboflavin, is involved in several essential metabolic processes within the cell, in particular DNA synthesis, repair, and methylation. Folate is also essential as a methyl donor

INFLUENTA FOLATULUI IN METILAREA ADNFigure 4. Possible mechanisms by which folate deficiency or excess may influence telomere structure and function: indentifiesplausible but untested mechanisms.

2. Structura cromatineiCromatina- organizata in 2 nivele: - heterocromatina silentiata (telomere, regiuni pericentrice, secvente repetitive) -eucromatina activa (genele active)

Nucleosom = unitatea de baza a cromatinei (ADN dublu catenar infasurat in jurul octamerului histonic). Miezul histonic - 2 copii ale fiecarei histone (H2A, H2B,H3 si H4) Lodish, 2000

Caracteristicile modificarilor post-translationale ale histonelor

sunt modificari chimice, covalente, dinamice si reversibile; nu sunt aleatoare; realizate de enzime- factorii de initiere: -semnale endogene - etapa de dezvoltare - tipul de tesut - semnale exogene - factori de mediu

Rolul: - afecteaza organizarea secundara a cromatinei - realizeaza interactii intre ADN si histone

Modelare expresie genicafenotip

Tipuri de modificari post-translationale ale histonelor Modificarile se realizeaza la aminoacizii din capatul N-terminal al histonelor

Dupa Tomasi TB et al, 2006

Modularea transcrierii Acetilarea si metilarea sunt considerate modulatorii cheie ai activarii si represiei transcriptionale

Rodenhiser D, Mann M, 2006

Mecanism metilare oncogenFig. 2. (a), aberrant methylation keeps occurring. After several clonal selections during multistep carcinogenesis, all cancer cells come to have methylation of multiple CGI. In contrast, if a cancer cell is derived from a precursor cell with methylation of multiple CGI (b), cancer cellsderived from it will also display methylation of multiple CGI.

CELULE STEM REPROGRAMATEJohn B. Gurdon a descoperit n 1962 faptul c specializarea celulelor este reversibil.

n cadrul unui experiment devenit clasic, el a nlocuit nucleul celular imatur dintr-o celul ou (embrionar) de broasc cu nucleul prelevat de la o celul intestinal matur. Celula embrionar modificat s-a dezvoltat ntr-un mormoloc de broasc normal. El a demonstrat c ADN-ul celulei mature, dei specializate, dispune de toate informaiile necesare pentru dezvoltarea tuturor celorlalte celule specializate care alctuiesc organismul broatei.

Shinya Yamanaka reuseste s reprogrameze celule mature de oareci pentru a deveni celule stem (imature, nespecializate).

n mod surprinztor, prin introducerea a doar ctorva gene, el a reuit s reprogrameze celulele mature n celule stem pluripotente - celule imature, capabile s se specializeze n orice tip de celul a organismului.

CELULE STEM PLURIPOTENTE INDUSE SI SUPRAEXPRESIA FACTORILOR DE TRANSCRIPTIE

3. ARN necodificator (ncRNA)

Cel mai studiat ARNnc este microARN

microARN (miRNA)

Molecule mici de ARN endogen (22 nucleotide), monocatenar, necodificatorSe leaga la capatul 3 (3UTR) al unui/unor ARN mesager specific(i)Moduleaza expresia genica prin - represarea expresia proteinei tinta- degradarea ARNm specificPoate controla direct structura cromatinei tintind factori implicati in remodelarea acesteia (conexiune cu PcG)In imunologie, miRNA sunt considerati reglatori cheie in angajarea pe o linie de diferentiere, maturare, mentinerea homeostaziei

The Increasing Complexity of the Central Dogma of Molecular Biology.Feero WG et al. N Engl J Med 2010;362:2001-2011.

Biogeneza/ actiune

Istoria miRNA

miRNA in hepatopatii

EXOZOMExozomii au markeri de suprafata CD63, CD9, CD81.

Deriva din linie hematopoetica :reticulocite, trombocite si limfocite .Pot fi secretati si de celule tumorale epiteliale ( neo pulmonar, renal, intestinal).

Studii recente au demonstrat ca pot transporta mRNA si microRNA.

Datorita diversitatii de transport au fost asociati cu mecanismele de polarizare a celulelor epiteliale, neuronale si crestere tumorala.

In studiile clinice se evalueaza nivelul exozomilor in sange, plasma, urina, lichid amniotic si lichide neoplazice.

In 2003 scientists in the Human Genome Project achieved a long-sought goal by obtaining the DNA sequence of the 3.2 billion base pairs (the order of As, Ts, Cs, and Gs) making up the human genome. The DNA sequence spells out the exact instructions needed to maintain and reproduce a living organism whether its a person, a plant, or a paramecium.Some fascinating insights so far:- The human genome is almost (99.9%) exactly the same in all people.- Only 2% of the human genome contains genes, the part of DNA that encodes recipes for proteins. We dont know what the remainder does.- We have an estimated 30,000-40,000 genes; the functions remain unknown for more than half of these.- Almost half of all proteins predicted from human genes share similarities with fruit flies and worms, underscoring the unity of life.- MUCH remains to be learned! Table 1 Representative Genomewide Association Studies of Common Cardiovascular Diseases.**Figure 2. Application of iPSC technology for cancer research.Reprogramming technology is considered to be a useful tool to induce global epigenetic changes and to alter differentiation status of cancer cells. (a) Reprogramming of cancer cells and differentiation of the cancer cell-derived iPSCs. Cellular reprogramming actively modifies the epigenetic/differentiation state of cancer cells without affecting its genetic constitution. The reprogrammed cancer cells may provide a novel platform todemonstrate the concept of cell type-specific carcinogenesis andto identify the cancer cell origin. (b) Cancer modeling. Expression of Yamanaka 4 factors can reprogram somatic differentiated cells into undifferentiated stem cells with unlimited proliferation properties. Reprogramming technology might be available to model reprogramming-associated cancers, which is accompanied by dedifferentiation process with altered epigenetic regulations.*Figure 1. The Increasing Complexity of the Central Dogma of Molecular Biology.The flow of genomic information from DNA to RNA to protein remains the basis for understanding genomic function (Panel A). A single gene can yield an extensive array of gene products, depending on the environment in which it is expressed, thereby expanding the repertoire of the 20,000 or so genes in the human genome (Panel B). The initial event of gene expression, transcription, is regulated by means of a complex choreography of events involving the three-dimensional DNA structure, covalent chemical, or epigenetic, modifications of the DNA backbone, and interactions between protein and DNA and between RNA and DNA. Translation is similarly complex and tightly regulated by interactions between messenger RNA (mRNA) and proteins. Processing of single-precursor RNA (preRNA) molecules can yield multiple RNA products, including microRNA (miRNA) and small interfering RNA (siRNA) molecules. Post-translational modification of proteins also contributes greatly to the diversity of the output of the human genome through modifications of individual immature proteins (e.g., folding, cleavage, and chemical modifications), which yield an array of related protein products.