Chapter 22
Genetics and Genetically Linked Diseases
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Genetics
• Study of how genes are transmitted from
parents to offspring
• Mutations
• Human genome
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Gene Mutations
• Occur occasionally at random in all cells
• Somatic cell mutation
• Chromosomal mutation
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Lethal Genes (1 of 2)
• Inherited mutations generally have negative
consequences for individuals
• An inherited gene that results in death is a
lethal gene
• The time at which lethal genes exert their
deadly influence varies
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Lethal Genes (2 of 2)
• Each person may carry 2–3 different
recessive lethal genes
• Two similar recessive genes must be
present in an individual for the gene to be
expressed
• People with common ancestry are more
likely to share many genes
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Human Genetic Disorders (1 of 3)
• Difference between genetic disorders and
congenital disorders
• Phenylketonuria
• Sickle cell anemia
• Tay-Sachs disease
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Human Genetic Disorders (2 of 3)
•
•
•
•
Duchenne’s muscular dystrophy
Huntington’s disease
Cystic fibrosis
Thalassemia
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Human Genetic Disorders (3 of 3)
• Hemophilia
• Chromosomal aberrations
• Mutagenic agents
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Genetic Counseling
• Talking with parents or prospective parents
about the possibility of genetic disorders
• Individuals who may benefit from
counseling
• After careful analysis a genotype is
determined
• Diagnostic tests
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Advances in Genetics
• Genetic engineering
– Manipulation of genes
• Gene therapy
– Correcting defective genes
© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.