Lecture 24: the human genome & disease Flashcards
mutations are…
permanent changes to the DNA sequence
mutations can be…
inherited or acquired
mutations that are inherited are called…
germline mutations
germline mutations are passed on via…
the gametes (sperm/eggs)
mutations xan also be acquired by somatic cells if DNA gets…
damaged or copied incorrectly
somatic mutations are ….. passed to the next generation
not
genetic variation/mutations are a driving force for…
evolution
mutations can have 1 of 3 effects on an organism they are:
- beneficial
- no effect
- deleterious (damageing/harmful) effect on the organism
the effect of most mutations is…
no effect
outcome of a mutation can also depend on:
- environmental factors
- other genes
example of an environmental factor that mutations can depend on:
- diet
- exposure to toxins
humans are diploid which means they have…
two copies of each of their genes (one maternal/paternal)
a mutation can either be…
heterozygous or homozygous
dominant mutation causes…
a phenotype when heterozygous
recessive mutation causes…
a phenotype when only homozygous
for a mutation to have a phenotype it must…
affect the function of a gene
a mutation might break a gene causing it too…
not work as well as normal/or might not work at all
mutation that causes a gene not to work as well/work at all is called…
a “loss of function” mutation
loss of function mutations are often…
recessive
loss of function mutations are usually recessive because…
the second chromosome can replace the loss of function on the defected one
a mutation that causes a gene to work too well, or do something unexpected is Called…
a “gain if function” mutation
gain of function mutations are often….
dominant
gain of function mutations are often dominant because…
they will not be replaced by the normal copy of the gene
example of an autosomal recessive mutation
- inability to taste PTC
- cystic fibrosis
example of an autosomal dominant mutation
- widows peak
- Huntington’s disease
example of an w-linked recessive mutation
haemophilia A/B
polygenic disorders involve…
several genes acting together or environmental factors interacting with genes
example of polygenic disorders include:
- diabetes
- obesity
most genetic disorders are ….. not deterministic
probabilistic
