Deletion

Definition

Deletion refers to a genetic mutation involving the loss of a segment of DNA from a chromosome, which can affect the structure and function of nucleic acids. This alteration can lead to significant changes in gene expression and protein synthesis, potentially resulting in various genetic disorders or diseases. Understanding deletions is crucial in the study of molecular biology, genetics, and their implications for health and disease.

5 Must Know Facts For Your Next Test

1. Deletions can vary in size from a single nucleotide to large segments of chromosomes, affecting multiple genes.
2. If a deletion occurs within a coding region of a gene, it can result in frameshift mutations that alter the entire protein product.
3. Some deletions can be inherited while others occur spontaneously during DNA replication or due to environmental factors.
4. Certain genetic disorders, such as cri du chat syndrome and some types of muscular dystrophy, are directly caused by specific deletions.
5. Detection of deletions often involves techniques like PCR amplification, comparative genomic hybridization, or next-generation sequencing.

Review Questions

• What are the potential consequences of a deletion mutation within a gene's coding region?
  • A deletion mutation within a gene's coding region can lead to significant consequences such as frameshift mutations. These frameshifts change the reading frame of the mRNA, potentially producing a completely different protein or truncating it entirely. This alteration can disrupt normal cellular functions and lead to various diseases or phenotypic changes depending on the affected gene's role in the organism.
• Discuss how deletions contribute to genetic disorders and give examples of specific conditions caused by such mutations.
  • Deletions contribute to genetic disorders by removing critical portions of DNA that may contain essential genes or regulatory elements. For example, cri du chat syndrome is caused by a deletion on chromosome 5, leading to severe developmental issues. Similarly, certain types of muscular dystrophy are linked to deletions within genes responsible for muscle function. These examples highlight how deletions can disrupt normal biological processes and result in profound health impacts.
• Evaluate the methods used to detect deletions in genomic DNA and their importance in clinical genetics.
  • Detecting deletions in genomic DNA is crucial for understanding genetic disorders and involves several techniques such as PCR amplification, where specific regions of DNA are selectively copied to identify missing segments. Comparative genomic hybridization allows researchers to visualize chromosomal abnormalities across the entire genome. Next-generation sequencing provides detailed information about genetic variations, including deletions. These methods are essential for accurate diagnosis and management of genetic diseases, guiding treatment options and genetic counseling for affected individuals.

Related terms

Mutation: A permanent alteration in the DNA sequence that makes up a gene, which can lead to changes in protein structure and function.

Chromosomal Aberration: Structural alterations in chromosomes, including deletions, duplications, inversions, or translocations, which can lead to genetic diseases.

Gene Expression: The process by which information from a gene is used to synthesize a functional gene product, usually proteins, which can be significantly affected by deletions.