GENE20001 Lecture Notes - Lecture 7: Zygosity, Wild Type
Genes might be disrupted/modified at inversion breakpoints. A form of mutation
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In meiotic pairing, the chromosome without the deletion forms a loop so it does not have to
pair with the other chromosome with a deletion.
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Here we have a duplication in one chromosome and deletion in another
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If you see a banding pattern in one chromosome but not in the homologous chromosome this
indicates a deletion
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On the top chromosome are mutant alleles. Chromosome on the bottom is all wild type
except for a deletion.
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So when we assay for the phenotype we should see b and c being expressed. If we can
map out the deletion break point it allows us to identify the genes that cause b and c.
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This phenomenon is known as pseudodominance (inheritance of an autosomal recessive
trait mimics an autosomal dominant pattern)
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Deficiency (deletion) mapping
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Deletion
Important for evolution of multi-gene families
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Can be associated with genetic diseases
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Duplication
Genetics Page 5
Document Summary
In meiotic pairing, the chromosome without the deletion forms a loop so it does not have to pair with the other chromosome with a deletion. Here we have a duplication in one chromosome and deletion in another. If you see a banding pattern in one chromosome but not in the homologous chromosome this indicates a deletion. Chromosome on the bottom is all wild type except for a deletion. So when we assay for the phenotype we should see b and c being expressed. If we can map out the deletion break point it allows us to identify the genes that cause b and c. This phenomenon is known as pseudodominance (inheritance of an autosomal recessive trait mimics an autosomal dominant pattern) Note the duplication forms a loop and does not pair with homologue. Chromosomal duplications important for evolution of multi-gene families. Duplications allow organisms to gain new functions or modify functions, allowing the organism to evolve.
