There is, provided the expedition is completed for solely scientific purposes, nothing inherently wrong with studying the genetic variations between races, variations in intelligence quotient, anatomy, or behavior of the human species. In fact, these studies are indeed carried out daily to some extent, but generally focus less on the individual races than humanity as a whole. There's a number of factors for this, namely that by and large humans of all "races" are not genetically distinct enough to merit individual research except in areas that are likely to return information, discovery, or really, monetary reward.

An example of just what I mean would be the sickle-cell trait, which has well known drawbacks to include death, and unexpected benefits such as added malarial resistance. It is most often attributed to the African continent, but arises in portions of the Middle East and even lower Mediterranean Europe. Generally, people view this mutation in a negative connotation because in the modern era this condition is more problematic than beneficial, in that it reduces effective blood flow, transfer of oxygen and nutrients essential to muscular fitness, and the aforementioned risk of death. Reasonably one could view this as a "deficiency" in race, but that is applying a modern perspective to something that might have been more historically or even prehistorically beneficial, having only since in recent times been obsoleted more or less. A single example, but proof enough that nothing is ever simple.

However, such a mutation is just that, a mutation and only remarkable to some extent in this case because it affects a certain population of people (in virtually all cases). It is neither significant enough to help classify that person as another "race", rather a subspecies, nor is it a reasonable place to say those people with it are somehow irredeemably defective. This only expands further as you look at the general population of humans in that while each race has clusters of beneficial qualities or detractions, none of them, even when in totality, are enough to merit categorization as anything other than the modern human, Homo sapiens sapiens.

At this point you might ask where I am going with this, which is entirely reasonable. I am shuffling us toward the topic of genetic pooling and how, speaking from a strictly biological approach, "pure bloods" are actually at very minor disadvantage to those who are "mixed" in heritage when talking about human beings.

Humans are a terrible example for this because they have a tremendous amount of genetic diversity even among "pure races", largely owing to how widespread as a species they are, but this holds some truth even then. Taking any population and only allowing it to breed among itself reduces its pool of genetic quality (this is of course ignoring some extent where the population is so big that it is unlikely to have much overlap), which people see most often and extreme with inbreeding, but the general effects otherwise are likely to be relatively negligible. The numbers of drawbacks, as one imagines, just increase the smaller and more consolidated that population gets and the more genetically similar it becomes. Now, there is no "race" small enough for this quality to really manifest with in full at the moment to be a separate species, but in theory you degrade the amount of beneficial mutations or synthesis of new material by limiting that pool to just what it has and nothing outside it. It would take an extended period, tens if not hundreds of thousands of years, to really see anything come from this.

If you were then to cross over with another unrelated race who shared minimal ancestry, adding a dash of it to a line, you get a very, very diluted form of hybrid vigor; certainly no supermen or universally "better" humans. This act does more or less add back in a larger selection that was missing, but genetically available, meaning some traits that might been active or unavailable can be spurred into motion. This tends to trend beneficially just by helping to avoid consolidated defects, but again, you are not looking at something as extreme as a human version of a liger, wolfdog or zonkey. This might however, result in sought after attributes coming together through what amounts to selective breeding. The problem with that being that humans reproduce relatively slowly and are much more prone to external influences than internal ones; the nurture to the nature. But, this might still result in someone who has say, both a gene that has a higher threshold for muscle growth and density from one parent, as well as aerobic capacity and bone tensile strength from another.

Why? Because these qualities are not really consolidated to one race. African heritage might have a better record of athleticism, but they still might have inactive genes which Northern Europeans possess. If one were to bring them together, it is now possible to get the best of both, though that is very unlikely. You are going to see a general wash, unless of course your outbreeding is from an extreme. A severely inbred population is going to see much more notable benefit from outbreeding than a relatively diverse population, because that limited band of options was greatly expanded.

Outbreeding tends to be for the better in general, but nothing is easily assured with this.

I must note however these are all extreme cases. The average "mixed race" human being is still going to be generally close enough to someone who is genetically "pure" and both are certainly still humans (just as much as a tabby cat bred with a tuxedo will still produce housecats despite their difference "races"). There's a lot more issues that have to deal with human social function that influence this than the genetic aspect; the "save everyone" mentality, limited amount of predators or dangers, long life spans, advent and access to technology and so forth. It is just not worth writing home about. There's discoveries to be made, but most of them can be cracked from just about any human's genetic material rather than a specific people's.

Intelligence and behavior are mostly influenced by the product of environment and less biologically so for humans. This area becomes an absolute grey mess as one dives into it because human beings are the only "thinking animal", or at least the only truly sapient, sentient one on Earth. It is very difficult to study them in the same fashion would say, a dog or dolphin, whose individual members are more or less almost entirely instinctual and thus can be held to pretty uniform standards. People have too many factors, past, present, and future to account for even in controlled settings. Large numbers of surveys tend to almost always be more accurate, but this is more important than ever when dealing with humans to gain a better average; polling from across the globe.

Yes, some races might have higher mental potential than others, but the difference is less profound than those found physical. I say this because it is far, far easier for a group of subjects in a test to train their muscles to their maximum biological limit and measure the weight they can lift by race alone, than their theoretical maximum mental faculties. The level of complexity and error grow massively in such environments, but these tests could be repeated over an extended period too.