医学遗传学 04基因突变的分子机制
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Hereditary mutations are carried in the DNA of the reproductive cells. When reproductive cells containing mutations combine to produce offspring, the mutation will be in all of the offspring's body cells.
Medical Genetics
Acquired mutations are changes in DNA that develop throughout a person's lifetime.
Medical Genetics
Although mistakes occur in DNA all the time, especially during cell division, a cell has the remarkable ability to fix them. But if DNA repair mechanisms fail, mutations can be passed along to future copies of the altered cell.
(5) Loss-of-function (null) mutations (lof)
result in no gene function are usually recessive although some haploinsufficient dominant "lof" mutations exist.
Medical Genetics
Medical Genetics
When a gene contains a mutation, the protein encoded by that gene is likely to be abnormal.
Medical Genetics
Medical Genetics
Medical Genetics
(4) Biochemical mutations
result in the inability to carry out a specific biochemical pathway (inborn errors of metabolism).
Medical Genetics
Medical Genetics
The fact that every cell contains the gene change makes it possible to use cheek cells or a blood sample for gene testing.
Medical Genetics
Medical Genetics
1.Genes can be mutated in many ways
The most common gene change involves a single base mismatch--a misspelling--placing the wrong base in the DNA. At other times, a single base may be dropped or added. And sometimes large pieces of DNA are mistakenly repeated or deleted.
result in altered gene function that act as a dominant allele and produces a novel phenotype.
Medical Genetics
Medical Genetics
Medical Genetics
3. Types of mutation effects
(1) Morphological mutations
give rise to altered forms.
Medical Genetics
Medical Genetics
Medical Genetics
2. Somatic versus germline mutations
Gene mutations can be either inherited from a parent or acquired.
Medical Genetics
Medical Genetics
Medical Genetics
(2) Lethal mutations result in nonviable organisms.
Medical Genetics
(3) Conditional mutations
gives a mutant phenotype under restrictive conditions (environmental) and causes a wild type phenotype under permissive conditions.
Medical Genetics
Medical Genetics
A common lof mutation is the partial loss-of-function or "leaky" mutation.
Βιβλιοθήκη Baidu
Medical Genetics
Medical Genetics
(6) Gain-of-function mutation (gof)
Medical Genetics
Acquired mutations are changes in DNA that develop throughout a person's lifetime.
Medical Genetics
Although mistakes occur in DNA all the time, especially during cell division, a cell has the remarkable ability to fix them. But if DNA repair mechanisms fail, mutations can be passed along to future copies of the altered cell.
(5) Loss-of-function (null) mutations (lof)
result in no gene function are usually recessive although some haploinsufficient dominant "lof" mutations exist.
Medical Genetics
Medical Genetics
When a gene contains a mutation, the protein encoded by that gene is likely to be abnormal.
Medical Genetics
Medical Genetics
Medical Genetics
(4) Biochemical mutations
result in the inability to carry out a specific biochemical pathway (inborn errors of metabolism).
Medical Genetics
Medical Genetics
The fact that every cell contains the gene change makes it possible to use cheek cells or a blood sample for gene testing.
Medical Genetics
Medical Genetics
1.Genes can be mutated in many ways
The most common gene change involves a single base mismatch--a misspelling--placing the wrong base in the DNA. At other times, a single base may be dropped or added. And sometimes large pieces of DNA are mistakenly repeated or deleted.
result in altered gene function that act as a dominant allele and produces a novel phenotype.
Medical Genetics
Medical Genetics
Medical Genetics
3. Types of mutation effects
(1) Morphological mutations
give rise to altered forms.
Medical Genetics
Medical Genetics
Medical Genetics
2. Somatic versus germline mutations
Gene mutations can be either inherited from a parent or acquired.
Medical Genetics
Medical Genetics
Medical Genetics
(2) Lethal mutations result in nonviable organisms.
Medical Genetics
(3) Conditional mutations
gives a mutant phenotype under restrictive conditions (environmental) and causes a wild type phenotype under permissive conditions.
Medical Genetics
Medical Genetics
A common lof mutation is the partial loss-of-function or "leaky" mutation.
Βιβλιοθήκη Baidu
Medical Genetics
Medical Genetics
(6) Gain-of-function mutation (gof)