Structural variants

Definition

Structural variants are large-scale alterations in the genome that can involve duplications, deletions, inversions, and translocations of DNA segments. These variants can have significant impacts on gene function and regulation, playing a crucial role in the genetic architecture of complex traits and diseases, particularly in the context of understanding genetic risk factors and cancer genomics.

5 Must Know Facts For Your Next Test

1. Structural variants can affect multiple genes and regulatory elements simultaneously, making them essential in studying complex traits and diseases.
2. They are often detected using advanced genomic technologies such as whole-genome sequencing and array comparative genomic hybridization.
3. Certain structural variants are associated with specific diseases, including various types of cancer, by altering gene expression or disrupting important genetic regions.
4. In polygenic risk scores, structural variants contribute to the overall genetic risk by adding layers of complexity beyond common SNPs.
5. Understanding structural variants is critical for precision oncology, as they can inform targeted therapies based on an individual's unique genomic makeup.

Review Questions

• How do structural variants contribute to the genetic architecture of complex traits?
  • Structural variants play a significant role in shaping the genetic landscape of complex traits by affecting multiple genes at once. Their large-scale nature means they can influence gene dosage, disrupt regulatory elements, or lead to genomic imbalances. This complexity adds another layer to how we understand heritability and the multifactorial basis of many diseases, making them vital for studying traits that don’t follow simple inheritance patterns.
• Discuss the implications of structural variants in cancer genomics and how they may guide precision oncology.
  • In cancer genomics, structural variants can lead to tumorigenesis by altering critical genes involved in cell growth and regulation. Identifying these variants can help tailor treatment options specific to a patient's unique tumor profile. Precision oncology leverages this information, aiming for targeted therapies that directly address the mutations present within an individual's cancer, potentially improving treatment outcomes significantly.
• Evaluate the role of structural variants in polygenic risk scores and their potential impact on predicting complex diseases.
  • Structural variants enhance polygenic risk scores by incorporating large-scale genomic changes that contribute to an individual's overall genetic susceptibility to complex diseases. Their inclusion allows for a more comprehensive understanding of genetic risk beyond what single nucleotide polymorphisms can provide alone. This approach offers a more accurate prediction model for disease susceptibility, enabling better prevention strategies and personalized medical interventions based on an individual's unique genetic profile.

Related terms

Copy Number Variation (CNV): A type of structural variant characterized by the presence of an abnormal number of copies of one or more sections of DNA.

Single Nucleotide Polymorphism (SNP): The most common type of genetic variation among people, where a single nucleotide in the genome differs between individuals.

Genomic Imbalance: A condition that arises when there is a difference in the number of copies of a particular region of the genome, often due to structural variants, leading to phenotypic consequences.