Podcast
Questions and Answers
What is the genotype for the colorblind son born to a woman with the genotype XcXc and a man with the genotype XCY?
What is the genotype for the colorblind son born to a woman with the genotype XcXc and a man with the genotype XCY?
All daughters from the cross between XcY and XCXC will be colorblind.
All daughters from the cross between XcY and XCXC will be colorblind.
False
What is the law of assortment?
What is the law of assortment?
The alleles of two or more different genes are sorted into gametes independently.
In the given example with mice, gray coat color is represented by the dominant allele _____ and white coat color by _____.
In the given example with mice, gray coat color is represented by the dominant allele _____ and white coat color by _____.
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Match the following traits to their corresponding dominant alleles in the mice example:
Match the following traits to their corresponding dominant alleles in the mice example:
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What does Mendel's dominant allele always show in?
What does Mendel's dominant allele always show in?
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In a test cross, one parent must have a dominant phenotype.
In a test cross, one parent must have a dominant phenotype.
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What is the purpose of a test cross?
What is the purpose of a test cross?
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Incomplete dominance results in a __________ phenotype.
Incomplete dominance results in a __________ phenotype.
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Which of the following traits can only be expressed by males?
Which of the following traits can only be expressed by males?
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Both genders can express X-linked traits.
Both genders can express X-linked traits.
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What are the genotype and phenotype ratios when breeding a pink flower with a white flower?
What are the genotype and phenotype ratios when breeding a pink flower with a white flower?
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Match the following traits with their description:
Match the following traits with their description:
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Study Notes
Mendelian Genetics
- Gregor Mendel is the father of genetics
- Mendel proposed that each parent contributes one allele, dominant or recessive, to an offspring. The dominant allele dictates the phenotype.
- Test cross: a method used to determine the genotype of an organism with a dominant phenotype
- Requires a parent with a known recessive genotype and a parent with an unknown genotype.
- Steps:
- Define alleles (e.g., A for dominant, a for recessive), using a consistent letter for each characteristic. Then state your parental (P1) cross by writing the genotypes using the letter you defined.
- Construct a Punnett square to predict possible offspring genotypes.
- Calculate genotype and phenotype ratios
- Produce a concluding statement that answers the posed question.
Non-Mendelian Inheritance
- Incomplete dominance: A blended phenotype. The heterozygote expresses a mix of the two homozygous phenotypes.
- Codominance: Both alleles are fully expressed.
- Example:
- A red flower crossed with a white flower results in pink offspring.
- A pink flower crossed with a white flower produces a mix of white and pink flowers.
Sex-Linked Traits
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Sex-linked traits are located on the sex chromosomes (X or Y).
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Normal traits are on autosomes.
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X-linked traits:
- Can be expressed in both males and females.
- Can be dominant or recessive.
- Examples: color blindness, hemophilia, Duchenne muscular dystrophy.
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Y-linked traits:
- Can be expressed only in males.
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Example:
- A colorblind woman and man have a son; the son is 100% colorblind.
- A colorblind man and a homozygous normal woman have a daughter; the daughter is 100% normal
Dihybrid Crosses
- Law of independent assortment: The alleles of different genes are sorted into gametes independently of each other.
- Dihybrid cross: crossing two individuals that differ in two traits.
- Example:
- A cross between a white heterozygous long-tail mouse and a homozygous gray short-tail mouse will result in a potential offspring of gray long tail, and gray short tail mice. The percentage of gray short-tail mice is half.
Pedigree Charts
- Pedigree charts are used to track the inheritance of traits through generations.
- Generations are numbered using Roman numerals (I, II, III).
- Individuals within each generation are numbered using Arabic numerals (1, 2, 3).
- Genotypes are often included.
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Description
Test your knowledge on Mendelian and non-Mendelian genetics concepts. This quiz covers key principles such as dominant and recessive alleles, test crosses, incomplete dominance, and codominance. Dive into the definitions and examples that shape the foundation of genetic inheritance.
