Why is Tₘ related to base composition?

Key Concepts

Tₘ (Melting Temperature)

Tₘ, or melting temperature, is the temperature at which half of the DNA strands are in the double-helix state and half are in the 'melted' single-strand state. It is a critical parameter in molecular biology, influencing the stability of DNA and the conditions required for processes like PCR and hybridization.

Base Composition

Base composition refers to the relative amounts of the four nucleotide bases (adenine, thymine, cytosine, and guanine) in a DNA molecule. The ratio of these bases affects the stability of the DNA double helix, as A-T pairs form two hydrogen bonds while G-C pairs form three, making G-C rich regions more thermally stable.

GC Content

GC content is the percentage of guanine and cytosine bases in a DNA molecule. Higher GC content generally correlates with a higher Tₘ due to the increased number of hydrogen bonds, which provide greater stability to the DNA structure. This relationship is crucial for understanding DNA behavior under varying thermal conditions.