![Page 1: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/1.jpg)
Genes, Populations,and the Environment
Biology Basics 3
![Page 2: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/2.jpg)
BB3.1 Genes and the Environment Interact More than genomes affects traits and diseases
Environmental factors include • Prenatal environment• What we eat, breathe• Where we live
Multifactorial traits, affected by both genetics and environment
![Page 3: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/3.jpg)
BB3.2 Genetics Affect Perception of and Response to Environment People’s senses react differently
Some people cannot taste a chemical called phenylthiocarbamide (PTC)
Genetic basis:• aa: Nontasters • AA or Aa: Tasters
![Page 4: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/4.jpg)
Population Distribution of Tasting
![Page 5: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/5.jpg)
Impact of Genetics on Food Choices
Two groups of tasters: tasters and supertasters
~25% of people are nontasters, ~50% are tasters, and ~25% are supertasters
May correlate with the aa, Aa, and AA genotypes
Supertasters can have > 10X taste buds as nontasters and have intense tastes
![Page 6: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/6.jpg)
Supertasters High-sugar foods too sweet, coffee is bitter, and
hot peppers and spices more intense, unpleasant
Less likely to include certain foods and beverages in diet
![Page 7: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/7.jpg)
BB3.3 Variations in Responses to Drugs and Medicines Range of reactions to drugs and medications,
may be genetically influenced Example: Rate metabolized affects dosage
Some capsules delay the release of the drug
Others drugs produced in variety of dosages
![Page 8: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/8.jpg)
BB3.4 Relationship between Cancer and Environment Indirect and direct evidence that environment
plays important role in cancer
Some environmental factors implicated in cancer• Natural radiation • Occupational exposure to chemicals • Virus infections • Personal choices: exposure to UV, smoking, and
diet
![Page 9: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/9.jpg)
Viral Infections: ~15% of Cancers
Viral infection alone is not enough to cause cancer, other factors involved
![Page 10: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/10.jpg)
BB3.5 Genetics and Cancer Therapy
> 70% breast cancer cases: estrogen sensitive
Tamoxifen treats estrogen-sensitive cancer
In body, inactive form converted to endoxifen
Conversion of tamoxifen to endoxifen controlled by CYP2D6
![Page 11: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/11.jpg)
Conversion of Tamoxifen to Endoxifen
![Page 12: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/12.jpg)
CYP2D6 Gene
Several alleles, four phenotypes One phenotype group metabolizes tamoxifen
poorly, higher risk of recurrence
Genetics important in designing or specifying drug therapy
![Page 13: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/13.jpg)
BB3.6 Behavior, Genes, and Environment
5-HTT gene controls nerve impulses in the brain
Variation may cause changes in stress-response behavior
Two alleles: one long and one short
Study of individuals ages 21–26 with ≥ 4 stress events, increased risk of depression for those with two copies of short allele
![Page 14: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/14.jpg)
BB3.7 Environmental Factors, Genes, and Immune System Autoimmune diseases: third most common
form of disease in U.S.• 15–80 diseases, affect 5–8% of population• Include: diabetes, multiple sclerosis, and
rheumatoid arthritis• > 75% of affected are women
![Page 15: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/15.jpg)
Distribution of Autoimmune Diseases
![Page 16: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/16.jpg)
Autoimmune Diseases
Body’s immune system produces antibodies that attack specific cells and tissues
Almost all tissues and organs can be affected
ID environmental agents that might cause disorder
Both genetic and environmental factors involved in triggering disease
![Page 17: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/17.jpg)
Autoimmune Diseases and Infections
![Page 18: Genes, Populations, and the Environment Biology Basics 3](https://reader033.vdocuments.us/reader033/viewer/2022050902/5a4d1b757f8b9ab0599b6ec9/html5/thumbnails/18.jpg)
BB3.8 Environment and Distribution and Frequency of a Genetic Disorder Populations and environment play a part in
genetics
Geneticists often look to environment for factors that may be responsible
In some cases, relationship between a gene and the environment is clearly established
In others cases, link is elusive and still unknown