Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Non-coding DNA wikipedia , lookup
Gene desert wikipedia , lookup
Promoter (genetics) wikipedia , lookup
Gene regulatory network wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Genomic imprinting wikipedia , lookup
Community fingerprinting wikipedia , lookup
Ridge (biology) wikipedia , lookup
Molecular evolution wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Chapter 1 The diversity of genomes and the tree of life Living organisms obtain energy in different ways - Organotrophic - Phototrophic - Lithotrophic - aerobic - anaerobic Some Cells Fix Nitrogen and Carbon Dioxide for others The greatest biochemical diversity is seen among procaryotic cells The phototrophic bacterium Anabaena cylindrica A lithotrophic bacterium, Beggiatoa, gets its energy by oxidizing H2S and can fix carbon even in the dark The tree of life has three primary branches: Bacteria, Archaea, and Eucaryotes The three - kingdom classification of organisms as proposed by Haeckel in 1866 Classification of organisms into five kingdoms first proposed by Whitaker in 1959. The five kingdoms were: Animalia, Planta, Fungi, Protista, and Monera Since molecular structures and sequences (of bases in DNA/RNA and of amino acids in proteins) are more revealing of evolutionary relationships than classical phenotypes (particularly among microorganisms), beginning in the 1950s, the basis for the definition of taxa shifted from the organismal to the cellular to the molecular level Universal phylogenetic tree in rooted form showing the three domains – Bacteria, Archaea, and Eucarya Some genes evolve rapidly; others are highly conserved Most Bacteria and Archaea have 1000 - 4000 genes Aug 31, 2004 Microbial Genomes – August 30, 2005 Microbial Genomes – complete; August 30, 2005 As of September 5, 2007 Eukaryotic Genomes – August 30, 2005 As of September 5, 2007 As of September 5, 2007 New genes are generated from preexisting genes Gene duplications give rise to families of related genes within a single cell Families of evolutionarily related genes in the genome of Bacillus subtilis 47% of the genes in this bacterium have one or more obvious relatives Paralogous genes and orthologous genes: two types of gene homology based on different evolutionary pathways Orthologs - genes in two separate species that derive from the same ancestral gene in the last common ancestor of those two species Paralogs - related genes that have resulted from a gene duplication event within a single genome, and are likely to have diverged in their function Homologs - genes that are related by descent in either way Paralogous genes and orthologous genes: two types of gene homology based on different evolutionary pathways Genes can be transferred between organisms, both in the laboratory and in nature Horizontal gene transfers in early evolution The function of a gene can often be deduced from its sequence More than 200 gene families are common to all three primary branches of the tree of life Mutations reveal the functions of genes Spotlight on E. coli We have a more thorough knowledge of the working of E. coli than of any other living organism, yet we hardly understand everything about this bacterium The major features of eucaryotic cells Eucaryotic cells may have originated as predators Eucaryotic cells evolved from a symbiosis Eucaryotes have hybrid genomes Eucaryotic genomes are big