Mendelian inheritance & Genetic basis of complex Inheritance Flashcards Preview

ME2308 Principles of Disease > Mendelian inheritance & Genetic basis of complex Inheritance > Flashcards

Flashcards in Mendelian inheritance & Genetic basis of complex Inheritance Deck (5)
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1

  • Describe the characteristics of Medelian Inheritance, both autosomal and sex-linked.

  • Autosomal
    • Dominant
      • Each generation is affected
      • Both sexes affected in equal proportion
      • Equally transmitted by both sexes
      • Transmitted through affected individuals
      • 50% chance of inheriting mutation (Only need 1 dominant allele)
    • Recessive
      • Affected individuals in a single generation
      • Generations “skipped
      • Both sexes affected in equal proportions

2

  • Describe the characteristics of Medelian Inheritance, both autosomal and sex-linked.

  • Sex Linkage
    • X-Linked Recessive
      • Males affected more than females, who have 2 copies of the X Chromosomes (hope for a dominant allele)
      • Transmitted through affected/unaffected females
      • Males cannot transmit disorders to sons
      • Daughters of affected males will be carriers
    • X-Linked Dominant
      • Both sexes affected
      • Females usually less severely affected than males
      • Affected males cannot transmit disorder to their sons
      • Daughters of affected males will be affected
    • Y-Linked
      • Affects males only

 

3

Anticipation- Triplet Repeat Expansion

Anticipation: Disease presents at earlier age and/or increasing severity in succeeding generations.

Triplet repeat diseases:

  - Huntington’s disease

  - Myotonic dystrophy (muscle wasting)

  - Fragile X syndrome (learning disabilities and cognitive impairment)

4

Homoplasmy and Heteroplasmy

Polyploidy: up to thousands mitochondria per cell.

Polyploid cells and organisms are those containing more than 2 homologous pair sets of chromosomes. 

2 - 10 copies per mitochondrion.

5

Genetic modifiers

Genes that have small quantitative effects on the level of expression of another gene. May involve polymorphism.