How do DNA molecules differ between species?

DNA molecules differ between species primarily in the number of genes and non-coding regions. This variation significantly influences an organism's characteristics and capabilities. Genes, which are segments of DNA that code for proteins, can vary in number and sequence from one species to another, impacting traits such as physical appearance, metabolic processes, and disease susceptibility. Non-coding regions, which do not code for proteins but can regulate gene expression and serve other functions, also show considerable variability across species.

This genetic diversity is a key aspect of the evolutionary process and contributes to the uniqueness of each species. The presence of different numbers of genes and non-coding regions can lead to significant differences in organismal structure, function, and overall biodiversity.

While the number of nucleotides and the variety of base pairs can also be factors in DNA differences, they are often results of the differences in genes and non-coding regions rather than primary distinguishing features. Similarly, the structure of DNA, including the arrangement of sugars and phosphates, is consistent across all species, as DNA's basic structure remains the same regardless of the species. Thus, focusing on genes and non-coding areas provides a clearer understanding of how DNA varies across different species.