BIOB 272 1st Edition Lecture 4Outline of Last Lecture I. ScalaNaturae (ladder of nature)A. Aristotle Thought1. Theory of Special Creation2. Species as Fixed Typesa. Carolus Linnaeus3. Enlightenment and Romantic Periodsa. Georges Buffon ideasb. Fossils-Georges Cuvierc. Jean Bapiste-earliest evolutionistd. Geologists to recognize gradual changei. James Huttonii. William Smith4. Charles Darwin (1809-1882) a. Charles Lyellb. Alfred Russel Wallace ideas5. Evolution=Descent with Modificationa. Examples of Species change through time:i. Beak length in Soapberry Bugsii. Vestigial limbs in contemporary whaleiii. Facultative bipedal to bipedal in apes/humans (transitional forms)b. Examples showing that all species are derived from common ancestors:i. Darwin’s phylogeny treeii. Homologyiii. Genome DNA sequenceiv. Genetic CodeOutline of Current Lecture I. DNA (deoxyribonucleic acid) II. Central DogmaIII. Genome1. 1st Genome RecordsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. Human Genome OrganizationA. Human extensive splicing complexity in humansB. Genome made of two types of DNA1. Euchromatic: 2. Heterochromatic DNAIV. Evolutionary GenomicsTimeline of Genomics KnowledgeCurrent LectureGenes and GenomesI. DNA (deoxyribonucleic acid) i. Molecule of Heredityii. G-C, T-A pairingII. Central Dogmai. Info flow through a cell: DNA----RNA---Proteina. DNA-DNA=replicationb. DNA-RNA= transcriptionc. RNA-mRNA-Protein= translation (used ribosomes to translate mRNA into protein) ii. Production of protein from DNA requires both transcription and translationiii. Francis Crick(1958,1970)iv. Most control takes place at the level of transcriptionv. Only about 20% of genes are expressed in a given (multicellular) eukaryotic cell at a given timevi. RNA splicing can create multiple proteins from a single gene because one RNA transcript makes many different mRNA transcripts- 1 gene can do many things functionallyvii. Proteins: chains of amino acidsIII. Genome:- The entire genetic complement of a living organism1. 1st Genome Records:i. First recorded sequence of human genome recorded:- February 2001- Cost $2.7 billionii. 2nd recorded sequence of human genome:- April 2003iii. Can now do it at most Universities/research labs for under $10,0002. Human Genome Organization- Eukaryotic DNA organized into chromosomes- Human genes: 23 homologous pairs of chromosomes (on chromosome chart ordered by size)- Genes occur in gene-dense “jungles” and gene-poor “deserts”Human extensive splicing complexity in humans:- About 22,000 genes overall - Largest gene has about 249 million base pairs and 2012 genes- Smallest gene has about 51 million base pairs and 432 genes- 6,000-10,000 transcripts expressed/human tissue- 95% multiexonic genes have multiple exons3. Genome made of two types of DNAA. Euchromatic: - Comprises 93% of DNA- Contains most of the genes in genome- 2.8 billion base pairs- 22,000 genes comprise about 2% of genomeo many fewer than expected, initial guesses were over 100,000 geneso many still have unknown function- 98% non-coding DNAo does not code for geneso function is unknown-but potentially very importanto Many repeated sequences( i.e. AGAGAGAGAGAG) and transposable elementsB. Heterochromatic DNA:- Comprises about 7% of DNA- Highly repetitive- Gene sparse- Very difficult to sequence, largely unexploredIV. Evolutionary Genomics: - comparing genomes of different species to learn about genome evolution and function- All organisms have about the same number of genes except e.coli and viruses- Gene number does not directly scale with complexity of organism V. Timeline of Genomics Knowledge:- 8000 BC: Neolithic farmers selected plants and animals with desirable traits (i.e corn)- 400 BC: Hippocrates (Greek philosopher) proposed blending inheritance- 350 BC: Aristotle dismissed Hippocrates theory noting that children do not always resemble their parents. His thinking was heredity centered on a mixing of “fluids” from each parent.- 1865-1900 ish: o Darwin’s Model of blending inheritance: Gemmules passed on to progeny through bloodstreamo Francis Galtonexperiment(1871)- blood transfusions in rabbits= showed that coatcolor was not altered by progenyo Gregor Mendel: contemporary of Darwin published paper in 1865-“On the Origin of Species”(1859)…unnoticed until 1900 Wanted to discover the mechanisms of inheritance that were needed for Darwin’s theory of evolution by natural
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