Podcast
Questions and Answers
Which scenario exemplifies pleiotropy?
Which scenario exemplifies pleiotropy?
- A gene influencing both eye color and susceptibility to a specific virus. (correct)
- Multiple genes contributing to the variety of human skin tones.
- Consuming an unhealthy diet leading to hypercholesterolemia in individuals without a predisposing genotype.
- Exposure to sunlight leading to an increase in melanin production.
Which of the following best illustrates the relationship between genotype and phenotype?
Which of the following best illustrates the relationship between genotype and phenotype?
- Genotype determines the potential range of traits, and phenotype is the actual expressed trait influenced by the environment. (correct)
- Phenotype is the complete set of genes in an organism, while genotype is the physical manifestation of those genes.
- Genotype is the observable trait, while phenotype is the genetic code that determines it.
- Genotype and phenotype are interchangeable terms describing an organism's physical characteristics.
A person has a genetic predisposition for above-average height. However, due to chronic malnutrition during childhood, they only reach average height. Which concept does this situation best illustrate?
A person has a genetic predisposition for above-average height. However, due to chronic malnutrition during childhood, they only reach average height. Which concept does this situation best illustrate?
- The interplay between nature and nurture in determining the phenotype. (correct)
- The overwhelming influence of environmental factors on the genotype.
- The impact of the genotype on the phenotype without environmental influence.
- An example of pleiotropy, where one gene affects multiple traits.
A scientist is studying a new species of plant. They observe variations in leaf shape, stem height, and flower color. Which of these observed characteristics would be considered phenotypes?
A scientist is studying a new species of plant. They observe variations in leaf shape, stem height, and flower color. Which of these observed characteristics would be considered phenotypes?
Considering both genetic and environmental factors, which individual is MOST likely to develop a darker skin phenotype?
Considering both genetic and environmental factors, which individual is MOST likely to develop a darker skin phenotype?
In humans, muscle tone is considered a phenotype. Which of the following factors could influence an individual's muscle tone phenotype?
In humans, muscle tone is considered a phenotype. Which of the following factors could influence an individual's muscle tone phenotype?
A plant breeder wants to develop a new variety of tomato with increased disease resistance. Would they focus on selecting plants with desirable genotypes or phenotypes, and why?
A plant breeder wants to develop a new variety of tomato with increased disease resistance. Would they focus on selecting plants with desirable genotypes or phenotypes, and why?
How do multiple genes typically influence a single phenotype, such as height or skin color?
How do multiple genes typically influence a single phenotype, such as height or skin color?
A scientist is studying a family with a history of both unusually high rates of nerve damage and a specific form of hormone imbalance. Which genetic phenomenon should the scientist investigate as a potential cause?
A scientist is studying a family with a history of both unusually high rates of nerve damage and a specific form of hormone imbalance. Which genetic phenomenon should the scientist investigate as a potential cause?
Cystic fibrosis results from a defective gene that affects the protein responsible for regulating salt and water balance in the lungs. This is an example of
Cystic fibrosis results from a defective gene that affects the protein responsible for regulating salt and water balance in the lungs. This is an example of
Flashcards
Phenotype
Phenotype
A physical trait or characteristic of an organism resulting from the interaction of its genotype and environment.
Genotype
Genotype
The genetic makeup of an organism that determines the phenotype.
Phenotype Examples in Plants
Phenotype Examples in Plants
Yellow or greed pod color, inflated or constricted pod shape, round or wrinkled seed shape.
Human Phenotype Examples
Human Phenotype Examples
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Genes and Phenotypes
Genes and Phenotypes
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Single Gene Phenotype
Single Gene Phenotype
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Pleiotropy
Pleiotropy
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Nature vs. Nurture
Nature vs. Nurture
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Environment & Phenotype
Environment & Phenotype
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Study Notes
- A phenotype is an organism's physical trait or characteristic resulting from the interaction of its genotype and environment.
- Phenotypes include both visible and non-visible traits, such as internal structures, proteins influencing metabolism, behavior, or disease susceptibility.
- A genotype is the genetic makeup that determines phenotype.
Phenotype Examples in Plants
- Gregor Mendel first observed phenotypes in his pea plant experiments.
- Mendel observed seven different phenotypes:
- Pod color (yellow or green)
- Pod shape (inflated or constricted)
- Seed shape (round or wrinkled)
- Seed color (yellow or green)
- Flower color (purple or white)
- Flower position (axil or terminal)
- Stem length (long or short)
- Mendel concluded that some traits were dominant and masked the recessive traits, but he did not know about genotypes.
- His work with plant phenotypes set the stage for genetic research.
Phenotype Examples in Humans
- Phenotype examples in humans include physical appearance, metabolism, and behavior.
- Observable traits are considered phenotypes and are a product of genotype and the environment.
- Some phenotype examples include:
- Skin color
- Height
- Eye color
- Immune strength
- Metabolic rate
- Muscle tone
- Hormone levels
How Genotypes Cause Phenotypes
- Genes are sections of DNA that code for proteins
- DNA is transcribed to mRNA, which is transported to the cytoplasm for translation.
- During translation, the ribosome reads the mRNA and builds a protein.
- A gene affects an organism's phenotype controlling which proteins are built.
- Cystic fibrosis, a lung disease, is controlled by one gene, where a defective gene at both alleles results in an incorrectly made protein that regulates salt and water balance in the lungs.
How Many Genes Can Affect a Single Phenotype?
- Many phenotypes are controlled by multiple genes and occur on a spectrum rather than a binary scale.
- Some examples of traits controlled by multiple genes include:
- Skin color
- Hair color
- Height
- Eye color
- Eye color is controlled by many genes, but scientists think the HERC2 and OCA2 genes control most of our eye color.
- These genes are important in producing melanin, the protein that creates pigmentation in our skin and eyes.
- Pleiotropy occurs when one gene controls two or more unrelated traits.
Nature vs. Nurture
- Phenotypes are generally a product of genotype, but the environment also plays a role.
- Many behavioral traits and complex physiological diseases have significant environmental components.
- Visible examples of how the environment can influence phenotype:
- High blood pressure
- High cholesterol
- Diabetes
- Alcoholism
- Metabolism
- Skin color is controlled by three genes, where the number of dominant alleles determines melanin production; melanin production is also influenced by sun exposure, so a person may have a darker phenotype than their genetics would determine.
- People who do not have the genotype for hypercholesterolemia can develop the condition by consuming an unhealthy diet.
- Humans are taller than they were hundreds of years ago due to changes in nutrition availability, an environmental factor.
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Description
Explore the definition and examples of phenotypes. Visible and non-visible traits, such as internal structures, proteins influencing metabolism, behavior, or disease susceptibility are discussed. Examples in plants and humans are provided.
