Evolution by Gene DuplicationSpringer Science & Business Media, 11 dec 2013 - 160 pagina's It is said that "necessity is the mother of invention". To be sure, wheels and pulleys were invented out of necessity by the tenacious minds of upright citi zens. Looking at the history of mankind, however, one has to add that "Ieisure is the mother of cultural improvement". Man's creative genius flourished only when his mind, freed from the worry of daily toils, was permitted to entertain apparently useless thoughts. In the same manner, one might say with regard to evolution that "natural selection mere(y tnodifted, while redundanry created". Natural selection has been extremely effective in policing alleHe mutations which arise in already existing gene loci. Because of natural selection, organisms have been able to adapt to changing environments, and by adaptive radiation many new species were created from a common ancestral form. Y et, being an effective policeman, natural selection is extremely conservative by nature. Had evolution been entirely dependent upon natural selection, from a bacterium only numerous forms of bacteria would have emerged. The creation of metazoans, vertebrates and finally mammals from unicellular organisms would have been quite impos sible, for such big leaps in evolution required the creation of new gene loci with previously nonexistent functions. Only the cistron which became redun dant was able to escape from the relentless pressure of natural selection, and by escaping, it accumulated formerly forbidden mutations to emerge as a new gene locus. |
Inhoudsopgave
1 | |
The Presence of Selfreplicating Nucleic Acids in Prebiotic Condition | 7 |
Emergence of Ribosomes | 13 |
Mutation and the Conservative Nature of Natural Selection | 21 |
Forbidden Mutations of Structural Cistrons | 27 |
References | 40 |
The Spontaneous Mutation Rate | 48 |
Why Gene Duplication? | 59 |
Duplication of Regulatory Genes and Receptors | 82 |
Elimination of Certain Chromosomes during Diploidization | 104 |
Part 5 | 111 |
Natures Great Experiment with Gene Duplication during | 124 |
Evolution from Amphibians to Birds and Mammals and | 132 |
Whence Comes Man? | 139 |
Subject Index | 147 |
Duplication of the Entire Genome | 80 |
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accompany the process acrocentrics active alanine alleles amino acid amino acid sequence amphibians anticodon appears autosomes base pair base sequence base substitution Biol centromere changes Chapter chromosomes cistron codon coli contains dehydrogenase deletion diploid duplicated genes enzyme evolution fish forbidden mutations function gene duplication genetic genome H-chains heavy-chains hemoglobin heterochromatin heterozygote heterozygous advantage histidine histones homologous homozygous horse immunoglobulin karyotype linkage lysine mammalian messenger RNA metacentric million years ago molecules mouse mutation rate myoglobin natural selection neutral mutations nucleic acid nucleolar organizer occurred OHNO peptide chain placental mammals polymorphism polypeptide chain Proc process of speciation produced protein redundant reptiles residues long ribosomal RNA Robertsonian fusions self-replication separate gene loci single gene locus somatic cells speciation species specified Spring Harbor Symposia strand structural cistron structural genes subunits synthesis tandem duplication tetraploid tolerable mutations transfer RNA tyrosine vertebrates wild-type