Genotype and phenotype
Genotype is the alleles an organism has. Phenotype is the feature you can see, such as eye colour.
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Analogy
Genotype is the recipe. Phenotype is the cake.
In practice
Two plants with genotypes TT and Tt both have the same phenotype: tall.
Practice
Flashcards
- What does heterozygous mean?Having two different alleles for a gene, such as Tt.
- What is the difference between genotype and phenotype?Genotype is the alleles you have. Phenotype is the feature you show.
Interview questions
- Explain how a Punnett square is used to predict the outcome of a genetic cross.
- Write the parents' alleles along the top and side
- Fill in each box with the allele pairs from both parents
- Work out the genotype of each box
- Count boxes to get probabilities or a ratio
Questions people ask
What do homozygous and heterozygous mean?
Homozygous means having two identical alleles for a gene, such as TT or tt. Heterozygous means having two different alleles, such as Tt. A heterozygous person shows the dominant feature, but can pass on the recessive allele and is called a carrier if the allele causes a disorder.
Does the environment affect phenotype?
Yes. Phenotype comes from genes and the environment together. Two identical twins have the same genotype, but one who exercises will be stronger. A plant with genes for tallness will still stay short without enough light or water. Many features, such as height and weight, are influenced by both.