Weird History These Pacific Islanders Don't Share DNA With Any Known Human Ancestor  

Lassie Smith
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In late 2016, researchers discovered a genetic gap in the DNA of Melanesians from Papua New Guinea, a gap which indicates a third, previously unknown ancestor of the Melanesian people. Needless to say, the scientific world went aflutter with speculation, postulating different theories as to who provided the missing link in Melanesian DNA. Already a highly isolated area featuring some of the world's most obscure countries, the Melanesian people developed a culture distinctively their own, including a number of unique ways to make mummies. Now they also boast one of the most unique genetic footprints of any other population, leading many to theorize the possible ancestry of the Melanesians. 

The search for the link within Melanesian DNA revealed a number of other strange and exciting facts about Melanesian peoples. They each possess genes from Neanderthals and Denisovans alike, and their genes also appear in American populations as well, meaning they traveled far beyond the realm of Oceania. Yet even all this information only gives researchers so many answers, as most answers, like the Melanesian people's third genetic ancestor, remain lost to time.

Melanesians Share Little In Common With Polynesians

Melanesians Share Little In Co... is listed (or ranked) 1 on the list These Pacific Islanders Don't Share DNA With Any Known Human Ancestor
Photo:  Internet Archive Book Images/WikiMedia Commons/CC BY-SA 3.0

Four major groups of Pacific Islanders - Malaysians, Melanesians, Polynesians, and Micronesians - were identified during the 19th century, with theorists asserting they shared the same origins and DNA. But during the early 21st century, DNA evidence proved Polynesians and Micronesians share little in common with Melanesians when it comes to genetics. Only after both Polynesians and Melanesians established themselves in Oceania did they meet and mix DNA with each other. 

Melanesians Trace Their Unique DNA Back To The Stone Age

Melanesians Trace Their Unique... is listed (or ranked) 2 on the list These Pacific Islanders Don't Share DNA With Any Known Human Ancestor
Photo: JimmyMac210 - just returned home from hospital/flickr/CC-BY-NC 2.0

In 2010, the genetic identity of Melanesians revealed itself to be even more of an outlier in Oceania. Research discovered Melanesians linked to not only European Neanderthals but to Denisovans, their eastern cousins, as well. Scientists knew Neanderthals migrated throughout the world thousands of years ago, but the appearance of their cousins' DNA in Melanesians came as a surprise.

The discovery of Neanderthal and Denisovan ancestry in Melanesia turned the genome world upside down. With assertions that Melanesian DNA was made up of anywhere from 3-6% of Denisovan DNA, scientists believed it points to a migration of the Denisovans out of Africa heading into east Asia some 300,000 years ago. There, they came in contact with the ancestors of the Melanesian people.

Neanderthals, Denisovans, And The New Hominid On The Block

Neanderthals, Denisovans, And ... is listed (or ranked) 3 on the list These Pacific Islanders Don't Share DNA With Any Known Human Ancestor
Photo: edenpictures/flickr/CC-BY 2.0

When scientists reassessed Melanesian DNA in 2016, they found a smaller contribution of Denisovan genetic material than previously thought. With less Denisovan ancestry present, another percentage of Melanesian DNA went up for grabs. Scientists posited that there must be a new and unidentified ancestor adding to the Melanesian mix. 

There Are No Remains Of This Potential New Ancestor - And Only One Denisovan Finger Remains

There Are No Remains Of This P... is listed (or ranked) 4 on the list These Pacific Islanders Don't Share DNA With Any Known Human Ancestor
Photo: mgstanton/flickr/CC-BY-NC-ND 2.0

Unfortunately, no remains of this third ancestor exist in the known fossil record. Experts only know of the Denisovan after a single pinky finger bone turned up in a cave in Siberia. With Denisovan DNA found in Siberia and Melanesia, the migratory activities of these groups can be extrapolated to a certain extent. Given that no archeological evidence exists of this third genetic ancestor either, it proves difficult to make any absolute assertions about its origins.