Gnetic basis of complex inheritance Flashcards Preview

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Flashcards in Gnetic basis of complex inheritance Deck (20):
1

Mendelian Inheritance (3)

Law of dominance
Law of segregation
Law of independent assortment

2

Non- mendelian inheritance

Does not fit in with Mendelian inheritance due to gene conversion and the ability of an intermediate phenotype

3

Anticipation

Eg triple repeat expansion

4

Extracellular inheritance

Eg mitochondrial DNA

5

Genomic printing

Variants from parents

6

Incomplete penetrance

Environmental factor
Genetic modifiers

7

Penetrance

Frequency with which trait is manifested by individuals carrying the gene
% with trait (mutant)/% with trait (wild) = RISK

8

Genetic modifiers

Genes that have small quantitative effects on level of expression of another gene - many involve polymorphism

9

Genomic imprinting

Genes expressed from only 1 chromosome so is parent of origin dependent and there is a higher risk of causing genetic disease

10

Epigenetic modifications

Heritable changes in gene function not explained by changes in DNA

11

Cytosine ( mC)

Induces structural adaption of chromosomal region so as to continue altered activity states

12

Anticipation - triple repeat

Disease presents at earlier age and/or increasing severity with age eg Huntingtons and myotonic dystrophy

13

Genetic mechanisms

Deletion, point mutation, imprinting error and uniparental disomy

14

Imprinting error (P)

Loss of maternal expression causing Angleman syndrome - epilepsy, awkward gait and retardation

15

Imprinting error (M)

Prader -wili syndrome - hypotonia short and obese

16

Uniparental disomy

Inheritance of a chromosome pair from one parental origin

17

Gyogenic

2 Maternal
Mass of embryo and ovarian teratoma

18

Androgenic

2 Paternal
Mass of placenta and Hydatidiform male

19

What does mitochondrial inheritance effect?

Tissue with high metabolic demand

20

Does mitochondrial DNA have a higher or lower mutation rate than nuclear DNA?

Higher - 100 fold more
Lack of DNA repair system and protective histones
Oxygen release radicals that attack DNA (mtDNA)