Question

One of the controversial issues, still, in evolutionary biology is the relative importance of DNA sequence variation vs. gene regulation in determining the adaptive value of protein variants. For example, at certain temperatures flies carrying the Adh-Fast allele have higher fitness than those carrying the Adh-Slow allele. Fitness is based on the flies' ability to metabolize ethanol in the rotting fruit in which the larvae live. However, how much of that fitness difference is based on the different catalytic properties of the two different proteins and how much is based on the concentration of enzyme in the cells (which is controlled by the regulation of Adh, no matter which allele it is), is an open question. Think about all you've learned about molecular evolution and offer your own assessment of the situation. More deeply, does this controversy have any parallels in the study of morphological characters?

Answer 1

The controversy in evolutionary biology surrounds the importance of DNA sequence variation and gene regulation in determining protein variant fitness. The contribution of catalytic properties and enzyme concentration is still unknown. This controversy has parallels in the study of morphological characters.

Step-by-step explanation:

The controversy in evolutionary biology regarding the relative importance of DNA sequence variation vs. gene regulation in determining the adaptive value of protein variants is a complex topic. In the case of flies carrying the Adh-Fast allele versus the Adh-Slow allele, their fitness in metabolizing ethanol is influenced by both the catalytic properties of the proteins and the concentration of enzyme in the cells, which is controlled by the regulation of Adh. The question of how much each factor contributes to the fitness difference is still open.

This controversy has parallels in the study of morphological characters as well. For example, the morphology of an organism can be influenced by the genetic sequence of the genes coding for structural proteins, as well as the regulation of gene expression that determines the concentration of those proteins in cells.

Overall, the study of both molecular and morphological evolution involves understanding the interplay between genetic sequence variation and gene regulation in determining adaptive traits.