Molecular Basis for

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Molecular Basis for Relationship between Genotype
and Phenotype
DNA
genotype
DNA sequence
transcription
RNA
translation
amino acid sequence
protein
function
organism
phenotype
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Mutation Levels of Hereditary Change
Gene (Point) Mutation One allele changes to a
different allele. Effects are limited to that
locus.
Chromosome Mutation Changes occur at the
chromosome level. Multi-locus effects are not
unusual.
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Types of Chromosome Mutations
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Changes in Chromosome Number I. Classes A. A
berrant Euploidy B. Aneuploidy II. Euploidy
A. Monoploid (x) chromosome number in a basic
set B. Euploidy multiples of monoploid number
C. Polyploid euploid with gt two sets of
chromosomes III. Examples of
Polyploidy A. Autopolyploidy multiple
chromosome sets from one species
B. Allopolyploidy chromosome sets from
different species
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Meiotic Pairing in Triploids
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Colchicine Induces Polyploidy
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Chromosome Pairing in an Autotetraploid
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Origin of the Amphidiploid Raphanobrassica
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Origin of Three Allopolyploid Species of Brassica
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Polyploidy in Animals
Parthenogenesis - development of unfertilized egg
into embryo polyploidy in leeches, flatworms,
brine shrimp polyploidy in salamanders,
lizards Polyploid frogs and toads undergo sexual
reproduction. Polyploid fish (such as salmon,
trout) are not unusual. Triploid oysters are of
economic value. In general, polyploid mammals
are not viable.