Final answer:
Genes for actin are highly conserved, meaning they have changed very little over time across different species, reflecting their essential role in cell functions and suggesting a common ancestry. The similarity in 3D structures of proteins across species even with differing amino acid sequences further underscores this evolutionary conservation.
Step-by-step explanation:
When genes are said to be highly conserved, it means that these genes have remained relatively unchanged throughout evolution and are very similar across different species. The genes for actin, which are involved in the cytoskeleton function of cells, are a prime example of such conservation. This high level of conservation is indicative of the essential functions that these genes serve; actins play a crucial role in cell motility and structure. Alterations in such genes could be detrimental to the survival of an organism, as seen with the essential role of ß-actin in embryonic development. Additionally, the ability of myosin from one species to interact with actin from another species suggests a deep evolutionary connection underlining their fundamental role in cellular processes.
Furthermore, the conservation of genes speaks to the common ancestry of all living things. The similar 3D structure of proteins like actin, despite minor differences in amino acid sequence between species, supports this concept. It also highlights the importance of gene conservation in tracing evolutionary relationships and understanding the evolutionary history of proteins that are critical to an organism's function and development.