15 Questions
What is the result of a change in gene frequencies within a population?
Evolution
Who is credited with describing natural selection and common ancestry?
Charles Darwin
What is the basis for the passing of traits from one generation to the next?
Genes
What stimulated extensive research in genetics during the 20th century?
The re-discovery of Mendel's work
What branch of biology combines the work of Mendel and Darwin?
Population Genetics
What is the primary source of variation required for natural selection?
Genes
What is the function of the protein tyrosinase in rabbits?
It catalyzes a chemical reaction that produces melanin
What is the term for a segment of DNA that codes for a protein?
Gene
What is the effect of a recessive allele on the production of melanin in rabbits?
It completely stops the production of melanin
What is the term for an individual that has two different alleles of a gene?
Heterozygous
What is the main difference between environmental effects on gene expression and allelic variations in genes?
Environmental effects are not heritable, while allelic variations are.
What is the primary goal of population genetics?
To study the evolution of populations at the level of genes and alleles.
What is the relationship between genes and traits?
Genes code for proteins that control traits.
What is the role of alleles in determining traits?
Alleles are variations of genes that can affect traits.
What would likely happen to the rabbit's fur coloration if it developed in the arctic?
Its entire body would be black due to the cold temperature.
Study Notes
Genes vs. Jeans
- Genes are the basis for the passing of traits from one generation to the next, while jeans are a type of clothing that can be changed frequently.
Evolution and Population Genetics
- Evolution is a change in gene frequencies within a population.
- Population genetics combines the ideas of Darwin and Mendel to explore how evolution works.
Genes and Alleles
- A gene is a segment of DNA that codes for a protein.
- Proteins determine traits, and changes in genes (mutations) cause changes in proteins, which produce variation in traits.
- Genes often have different forms, known as alleles.
- Alleles are responsible for the variation in traits.
Gene Expression and Environment
- The environment can influence the expression of a gene, but this influence is not goal-directed and does not result in heritable change.
- Environmental factors can affect the expression of some genes, but variations induced by the environment are not heritable (unless environmental factors mutate DNA).
Types of Alleles
- Dominant alleles can mask the effects of recessive alleles.
- Recessive alleles can cause changes in traits, such as albinism.
Rabbit Fur Coloration
- The gene for the enzyme tyrosinase controls the production of melanin, which determines fur color in rabbits.
- Different alleles of the tyrosinase gene can result in different fur colors, such as brown or albino.
- Temperature can affect the expression of the tyrosinase gene, resulting in variations in fur color.
Heritable Variation
- Heritable variations are determined by the variety of alleles, or different forms of genes, which build proteins.
- Genes and their alleles are the sources of heritable variations in traits.
Learn about the difference between genes and jeans, and discover how genes impact the passing of traits from one generation to the next. Explore population genetics and the concept of evolution.
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