Genes

Definition

Genes are segments of DNA that serve as the basic units of heredity, determining the traits and characteristics of an organism. They encode the information necessary for producing proteins, which play critical roles in cellular functions and overall development. Each gene can influence multiple traits, and their interactions contribute to the genetic variation observed within populations.

5 Must Know Facts For Your Next Test

1. Genes are located on chromosomes and each human cell contains approximately 20,000 to 25,000 genes.
2. Every individual has two copies of each gene, one inherited from each parent, which can lead to genetic variation through combinations of alleles.
3. Mutations in genes can lead to variations in traits and may be beneficial, harmful, or neutral depending on the environmental context.
4. Genes are regulated by other sequences in the genome that control their expression, determining when and how much protein is produced.
5. The principles of inheritance established by Gregor Mendel showed that traits are passed down through generations due to the behavior of genes during reproduction.

Review Questions

• How do genes contribute to genetic variation within a population?
  • Genes contribute to genetic variation through the presence of different alleles at specific loci on chromosomes. Each individual inherits a unique combination of alleles from their parents, resulting in diverse traits among members of a population. This variation is essential for natural selection, as it provides a pool of traits that can adapt to changing environments.
• Discuss how Mendel's experiments helped establish the understanding of gene inheritance.
  • Mendel's experiments with pea plants laid the foundation for our understanding of inheritance by demonstrating that traits are passed down through discrete units called genes. He observed patterns of inheritance, such as dominant and recessive traits, which illustrated how alleles segregate during gamete formation. These principles helped scientists recognize the predictable patterns of inheritance that govern genetic traits across generations.
• Evaluate the impact of mutations on gene function and how this relates to evolutionary processes.
  • Mutations introduce changes to gene sequences that can alter protein function, leading to new traits in organisms. Depending on the nature of these mutations, they can be beneficial, neutral, or detrimental. Beneficial mutations may confer advantages that enhance survival and reproduction, contributing to evolutionary processes like natural selection. Over time, this leads to an accumulation of favorable traits in populations, shaping the course of evolution.

Related terms

DNA: Deoxyribonucleic acid, the molecule that carries genetic information in all living organisms and some viruses.

Allele: Different forms of a gene that can exist at a specific locus on a chromosome, which can result in variations in traits.

Phenotype: The observable physical and physiological traits of an organism, which result from the interaction between its genotype and the environment.