1323383652_CHAPTER_5_SPR

1323383652_CHAPTER_5_SPR - EVOLUTION/LECTURE1 Evolution(PCB...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
EVOLUTION/LECTURE1 file:///E|/CH5-MUTATION-SPRING-2008/CHAPTER_5_SPR_2008.html[12/8/2011 2:29:34 PM] Evolution ( PCB 4674 ). Chapter 5. Mutations and genetic variation 1 Main topics of lecture: I: Mechanisms responsible for generating new genes and new alleles 1.- Introduction 2.- Where new alleles come from 3.- Where new genes come from II: Chromosome alterations: 4.- Inversions 5.- Polyploidy III: Measuring genetic variation in natural populations 6.- Genetic variation in natural populations: An introduction 7.- Determining genotypes using DNA 8.- How much genetic diversity exists in a typical population? I: Mechanisms responsible for generating new genes and new alleles 1.- Introduction 1.1.- Mutations are the raw material of evolution. Without mutation there are no new genes, no new alleles, and eventually no evolution. Mutation is the ultimate source of the heritable variation acted upon by natural selection and other evolutionary processes 2.- Where new alleles come from 2.1.- The instructions for making and running an organism are encoded in its heritable material: the molecule called deoxyribonucleic acid, or DNA. DNA is made of deoxyribonucleotides. Each on them contains: - 5-carbon sugar called deoxyribose - A phosphate group - A distinct nitrogen-containing base [Pyrimidines (Cytosine & Thymine) or purines (adenine & guanine) - The four deoxyribonucleotides are routinely abbreviated to C, T, A, and G depending on their distinct nitrogen bases 2.2.- Deoxyribonucleotides are linked by phosphodiester bonds that form between the
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
EVOLUTION/LECTURE1 file:///E|/CH5-MUTATION-SPRING-2008/CHAPTER_5_SPR_2008.html[12/8/2011 2:29:34 PM] 5' carbon of one deoxyribonucleotide and the 3' carbon of another. This form a single strand of DNA. However, in cells, DNA normally consists of two such strands and they wound around one another in the double helix. Hydrogen bonds are formed between the two strands, and they form bonds between "complementary" nitrogen-bases. These bonds can only be formed when Adenine and Thymine (A-T) and Guanine and Cytosine (G-C) bases line up on opposite strands. These purine-pyrimidine combinations are called complementary base pairs. Three hydrogen bonds form between G and C, but only two are made between A and T. (Fig. 4.1) 2.3.- The central dogma of molecular biology is that DNA is transcribed into messenger RNA (mRNA), which is then translated into protein: 3'-CAACGTCCGACAAGT-5' DNA (15 nucleotides) | V 5'-GUU GCAGGC UGUUCA -3' RNA (15 nucleotides, 5 codons) Alternate codons are underlined | V Valine Alanine Glycine Cysteine Serine Protein (5 amino acids)
Background image of page 2
EVOLUTION/LECTURE1 file:///E|/CH5-MUTATION-SPRING-2008/CHAPTER_5_SPR_2008.html[12/8/2011 2:29:34 PM] 2.4.- The genetic code is read in triplets called codons. There are 64 different codons, 3 of them are stop codon, one of them is a star codon (also for Methionine) and the rest code can code for 20 amino acids, therefore the genetic code is highly redundant, meaning that the same amino acid can be specified by more than one codon
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/11/2012 for the course PBC 4674 taught by Professor Ortega during the Spring '12 term at FIU.

Page1 / 18

1323383652_CHAPTER_5_SPR - EVOLUTION/LECTURE1 Evolution(PCB...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online