Mutations are changes in the DNA that can affect how genes, alleles, and chromosomes work together. It's important for Year 1 Biology students to understand these ideas.

Key Terms

1. Genes: These are pieces of DNA. They provide the instructions to make proteins and decide different characteristics, like eye color. Each gene is found in a specific spot on a chromosome.

2. Alleles: These are different versions of a gene. For example, a gene that controls flower color might have a red allele (R) and a white allele (r). Some alleles can be stronger than others, which we call dominant and recessive.

3. Chromosomes: These are structures made of DNA and proteins. They hold and organize genes. Humans have 23 pairs of chromosomes, which means we have 46 in total. Each chromosome has many genes.

How Mutations Affect Genes and Alleles

• Types of Mutations:

  • Point Mutations: These are small changes in the DNA, like switching a single letter (e.g., changing A to T). This can lead to a new allele.
  • Insertions and Deletions: These mutations either add or remove pieces of DNA, which can change how a gene works.
  • Copy Number Variations: These happen when larger chunks of DNA are repeated or left out.

• Effects on Alleles:

  • Mutations can create new alleles, changing how traits appear in a group of living things. It's estimated that about 1 in 1,000 parts of human DNA has a mutation.
  • Some mutations can be good, giving an advantage, while others may have no effect or could be harmful.

How Chromosomes Are Structured and What They Do

• Connection Between Chromosomes and Genes:

  • Each chromosome has many genes on it. When mutations happen, they can cause parts of chromosomes to be duplicated or rearranged. This can lead to serious health problems.

• Facts About Genetic Disorders:

  • About 7.5% of babies born around the world have some kind of genetic disorder, many caused by changes in chromosomes.

Conclusion on the Effects of Mutations

Mutations are crucial for evolution because they create variety within DNA. They can lead to:

• The creation of new alleles.
• Changes in the structure of chromosomes that might cause health problems or differences in species.
• About 95% of the genetic differences in humans come from mutations instead of things in the environment.

Learning how genes, alleles, and chromosomes are connected helps us understand genetics better. This knowledge is important for future studies in areas like medicine and farming.