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Gene Mutation - Coggle Diagram

- - - - Penetrance and expressivity: Many factors can affect gene expression. Some cause the expression of traits to deviate from the patterns predicted by Mendelian inheritance.
        
        Penetrance is how often a gene is expressed. It is defined as the percentage of people who have the gene and who develop the corresponding phenotype
        
        Expressivity is the extent to which a gene is expressed in a single person
        
        If a pedigree appears to skip a generation, consider incomplete penetrance, incomplete expression, and (less likely) genomic imprinting.
      - sex-limited inheritance
        
        A trait that appears in only one sex is called sex-limited. Sex-limited inheritance is distinct from X-linked inheritance, which refers to traits carried on the X chromosome. Sex-limited inheritance, perhaps more correctly called sex-influenced inheritance, refers to special cases in which sex hormones and other physiologic differences between males and females alter the expressivity and penetrance of a gene.
      - genomic imprinting
        
        Genomic imprinting is the differential expression of genetic material depending on whether it has been inherited from the father or mother. it is usually determined by effects that occur normally in the development of gametes. Changes such as methylation of DNA may cause certain maternal or paternal alleles to be expressed to different degrees.
      - codominance of alleles
        
        Codominant alleles are both observed. Thus, the phenotype of heterozygotes is distinct from that of either homozygote.
      - X chromosome inactivation.
  - - - Nutrients can induce gene expression thereby altering individual phenotype.
- - - - The mutation of the chromosomal segments of the DNA strands.
    - - Irregularities or accidents during cell division
        
        chromosomal structure changes
        
        translocation
        
        inversion
        
        deletion
        
        duplication
        
        insertion
        
        change in chromosome numbers
        
        aneuploidy
        
        polyploidy
    - - errors during other cell division (mitosis)
      - teratogens (substances)
        
        biological
        
        health conditions (e.g. diabetes)
        
        viruses & bacteria
        
        chemical
        
        alcohol
        
        tobacco
        
        toxic substances
        
        certain medications
        
        street drugs
        
        physical
        
        radiation
      - errors during sex cell division (meiosis)
        
        age - A woman age 35 years or older is at higher risk of having a baby with a chromosomal abnormality, because they born with all of their eggs already in their ovaries, so if a woman is 35 years old, the eggs are also 35.