Paragraphs 15-16 reveal the lack of consensus among experts regarding the spread of ancient domesticated cats' DNA, providing different theories and perspectives on the topic.
Paragraphs 15-16 contribute to the development of ideas in the text by revealing that experts are not in agreement about why ancient domesticated cats' DNA spread around the world.
This is evidenced by the statement that the debate over whether or when ancient Egyptian influence reached central and western Africa remains open, and that there is sparse but consistent evidence of people moving animals for thousands of years across different regions and civilizations.
These paragraphs suggest that there are different theories and perspectives regarding the spread of ancient domesticated cats, and highlight the ongoing exploration of this topic.