As researchers continue to probe the highly expressive vocal and postu

Good question! Oftentimes a couple different verb tenses work just fine in the same sentence, so you're right to not jump to conclusions about which tenses are "right" and "wrong" without doing some careful analysis.

Here we get a really good clue "as". "As" tells us that two things in the sentence are happening at the same time: "I walked the dog as the sun set", "I try to clean up as I cook dinner", "I have studied hard as the test has approached", etc. Because the two things are happening at the same time in the sentence, they should use the same tense. The tense is already established as present with "as researchers continue". So as researchers continue to probe, the wolves' resemblance to dogs becomes more clear.

Another quick note here: perfect tenses define a really specific, relative timeline — past perfect happens before a past event, present perfect happens before a present event, future perfect happens before a future event. So in this sentence, the use of present perfect would indicate that the wolves' resemblance to dogs becoming more clear is something that happened before the researchers continued to probe ... which doesn't make sense. Make sure you need a perfect tense before you use it! Otherwise, stick to simple tenses.