Final answer:
Closely-related species having different regulatory DNA sequences can result in variations in gene expression and phenotypic differences. These sequences control when and where genes are expressed, influencing the production of proteins and the development of traits.
Step-by-step explanation:
Closely-related species having different regulatory DNA sequences can result in variations in gene expression and phenotypic differences. Regulatory DNA sequences, such as enhancers and promoters, play a crucial role in controlling when and where genes are expressed. These sequences can determine the rate of transcription and influence the binding of transcription factors, which ultimately affects the production of proteins and the development of traits.
For example, let's consider two closely-related bird species with different regulatory DNA sequences for the gene responsible for feather coloration. One species may have a regulatory sequence that enhances the expression of this gene, resulting in vibrant colorful feathers, while the other species may have a regulatory sequence that represses the expression, leading to duller feathers.
Thus, the variations in regulatory DNA sequences among closely-related species can give rise to different phenotypes and contribute to the diversity of life on Earth.