DNA Flashcards
What is the term for a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule?
A codon is a sequence of three nucleotides that together form a unit of genetic code in DNA or RNA molecules.
What is a fusion gene?
A fusion gene is a hybrid gene formed by the abnormal joining of parts from two previously separate genes. This joining can happen due to errors in the way our DNA gets copied or rearranged during cell division.
Fusion genes. There are three main ways these can occur:
-Translocation: This is when a piece of DNA breaks off from one chromosome and attaches itself to a different chromosome. If this piece lands in the middle of a gene, it can fuse that gene with another nearby gene.
-Interstitial deletion: Sometimes, a piece of DNA gets deleted from a chromosome. If this deletion happens to remove the boundary between two genes, they can fuse together.
-Chromosomal inversion: In this case, a segment of a chromosome flips upside down. If this flipped segment includes parts of two genes, they can become fused.
Exons
Function: Exons are the coding sequences within a gene. This means they contain the instructions for building proteins.
Fate: Exons are included in the final, mature messenger RNA (mRNA) molecule that is used to create proteins.
Conservation: Exon sequences tend to be highly conserved, meaning they change very little over time because they are essential for protein production.
