Coding sequence

Definition

A coding sequence is the portion of a gene's DNA or RNA that is translated into a protein, consisting of a series of nucleotides arranged in codons. This sequence is crucial for the production of proteins, as it determines the amino acid sequence of the resulting protein, impacting its structure and function. Understanding coding sequences is essential for genome annotation and gene prediction, as they help identify genes and their functional elements within a genome.

5 Must Know Facts For Your Next Test

1. Coding sequences start with a start codon (typically AUG) and end with a stop codon (such as UAA, UAG, or UGA) in mRNA.
2. They can be interrupted by non-coding regions called introns, which are spliced out during RNA processing before translation occurs.
3. The length and composition of coding sequences vary widely across different organisms, influencing protein diversity.
4. Genome annotation tools utilize coding sequences to predict gene locations and functions, allowing researchers to understand gene regulation and expression.
5. Mutations within coding sequences can lead to changes in protein function, potentially resulting in diseases or altered traits.

Review Questions

• How do coding sequences relate to gene structure and function in the context of genome annotation?
  • Coding sequences are integral to gene structure as they contain the actual information needed to produce proteins. In genome annotation, these sequences help researchers identify where genes are located within the genomic DNA. By analyzing coding sequences, scientists can predict potential protein products and understand their functions, which is essential for mapping out biological processes and pathways.
• Discuss the role of exons and introns in relation to coding sequences and their impact on gene expression.
  • Exons are the parts of a coding sequence that remain in the final mRNA after splicing, while introns are non-coding segments that are removed. This structure allows for alternative splicing, where different combinations of exons can be joined together to create multiple protein isoforms from a single gene. This flexibility enhances the diversity of proteins produced and plays a significant role in regulating gene expression and responding to environmental signals.
• Evaluate the significance of mutations in coding sequences for evolutionary biology and medicine.
  • Mutations in coding sequences can have profound effects on protein function, potentially leading to beneficial adaptations or harmful diseases. In evolutionary biology, these mutations can drive natural selection by affecting an organism's fitness. In medicine, understanding how specific mutations alter protein function aids in diagnosing genetic disorders and developing targeted therapies, highlighting the importance of studying coding sequences in both fields.

Related terms

Gene: A segment of DNA that contains the instructions for building a particular protein or functional RNA molecule.

Exon: A segment of a coding sequence that is retained in the final mRNA after introns are removed during the processing of pre-mRNA.

Codon: A sequence of three nucleotides in DNA or RNA that corresponds to a specific amino acid or a stop signal during protein synthesis.