lukukehystä

Lukukehystä is a Finnish term that translates to "reading frame" in English. It is most commonly used in the context of genetics and molecular biology. A reading frame refers to the three possible ways in which a sequence of nucleotides in a nucleic acid molecule (like DNA or RNA) can be translated into a sequence of amino acids.

The genetic code is read in codons, which are triplets of nucleotides. For any given strand of nucleic acid, there are three possible starting points for reading these triplets. For example, if a sequence is ABCDEFG..., the three reading frames would be:

Frame 1: ABC, DEF, G...

Frame 2: BCD, EFG, ...

Frame 3: CDE, FGH, ...

The correct reading frame is determined by the start codon, which signals the beginning of protein synthesis. If the genetic information is read in the wrong reading frame, it will result in a completely different and usually non-functional protein sequence, or it may not produce a protein at all if a stop codon is encountered prematurely.

The concept of reading frames is crucial for understanding gene expression and for the analysis of DNA and RNA sequences. When scientists sequence DNA, they must consider all possible reading frames to identify potential protein-coding regions, known as open reading frames (ORFs). These ORFs are sequences that begin with a start codon and end with a stop codon, indicating a potential gene.