Genes, Genotype and Phenotype – Lesson Summary

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Learning Objective

In this lesson we will learn how characteristics of living things are influenced by genetic and environmental factors.

Learning Outcomes

By the end of this lesson you will be able to:

  • Describe what traits are and explain how they are influenced by genetic and environmental factors.
  • Describe what genes and alleles are and explain why individuals have two alleles for each gene.
  • Distinguish between homozygous and heterozygous individuals.
  • Distinguish between genotype and phenotype.

 
genes genotype and phenotype lesson contents

(Image: ROverhate, Pixabay)

Lesson Topics

1 | Heredity

2 | Traits

3 | Genes

4 | Alleles

5 | Homozygosity and Heterozygosity

6 | Genotype and Phenotype

7 | Summary

Lesson Summary

  • Genetic information encoded in DNA influences physical, biochemical and behavioural characteristics of organisms.
  • The transfer of this genetic information from parents to offspring is known as heredity or biological inheritance.
  • The study of heredity is called genetics.
  • A trait is a characteristic of an organism.
  • Traits include physical and non-physical attributes.
  • Quantitative traits exhibit continuous variation.
  • Qualitative traits fall into discrete categories.
  • Traits are influenced by both genetic factors and environmental factors.
  • Genetic components of traits are passed on from parents to offspring, but environmental components are not passed on.
  • Genes are sequences of DNA that code for specific products, usually proteins.
  • The production of proteins by a cell, based on instructions encoded in DNA, is called gene expression.
  • An allele is a variant of a gene that codes for a different version of that gene’s product.
  • An individual that is homozygous for a particular gene has two alleles that are the same.
  • An individual that is heterozygous for a particular gene has two alleles that are different.
  • The combination of alleles for a gene is referred to as an individual’s genotype.
  • The variant of a trait is referred to as an individual’s phenotype.
  • Genotype relates to genetic information stored in DNA whereas phenotype relates to observable characteristics.

 
genotype phenotype chromosomes

(Left image: _aine_, Adobe Stock)

(Header image: Fahkamram, Adobe Stock)