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The Genographic Project Explores the Ancient History of Guam

Latte stone pillars, unique to the Marianas Islands
Latte stone pillars, unique to the Marianas Islands. Photo by Miguel Vilar.

The name Micronesia, meaning small islands, describes the region well since most of these are small atolls, less than 80 square miles. I’m among the beautiful Marianas islands of western Micronesia, more specifically in Guam to meet the Chamorro people, and to see if together we could unlock some of the mysteries hidden in their DNA.

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Nearly half of Guam’s 160,000 people are Chamorro. Chamorros, the ethnic group of the Marianas, are thought to be descendants from the earliest settlers of Remote Oceania, and they likely reached the archipelago from the islands of Southeast Asia more than 3,500 years ago. Today, nearly all Chamorros speak English as well as their native Chamorro, which itself is a linguistic isolate among Pacific Island and East Asian languages, while also a relic of a distant connection between Guam and the islands of Southeast Asia.

But language is only one of the attributes that make Chamorros unique. Archaeologically the Marianas are home to massive stone pillars, some as tall as 5 meters, known as latte. These stones are often found standing in parallel lines, suggesting they may have functioned as large stilts that at one time held up buildings. Latte stones are found nowhere in the world except the Marianas.

Chamorros are also genetically unique. Our recent manuscript on mitochondrial DNA (mtDNA) diversity in the Marianas showed that Chamorros were distinctive from not only their Micronesian neighbors, but even across each island of the archipelago. However, that study was limited in scope since it looked strictly at maternally-inherited mtDNA. That brings me to one of the main purposes of my trip to Guam, we would like to analyze the paternally-inherited Y Chromosome DNA and the bi-parentally inherited autosomal DNA of Chamorros.

Chamorro man participating in the Genographic Project in Guam
Chamorro man participating in the Genographic Project in Guam. Photo by Miguel Vilar.

Over the course of two days of fieldwork, and on opposite coasts of Guam, I enrolled 85 participants in the Genographic Project. Participants joined after giving informed consent, providing demographic and genealogical information, and rubbing the inside of their cheek for 20 seconds with a swab designed to capture cheek cells. Each participant gave two swab samples, which were stored individually in buffer-filled test tubes and taken to the University of Pennsylvania for DNA extraction, amplification and sequencing.

What we will find in the DNA still remains a mystery, since we know Chamorros experienced hundreds of years of Spanish occupation, followed by American and Japanese occupation in the 20th century. And the proximity and historic connection to the Philippines will undoubtedly have played a role in the make-up of the Chamorro gene pool.

The Genographic Project, now in its eighth year, has enabled scientists around the world to fill in the blanks on mankind’s genetic maps of the world. These maps are enhanced every time we work with unique populations such as the Chamorros, and in many cases what we learn becomes incorporated into the history of a people.

Professors at the University of Guam are already using the mtDNA results we published in late 2012 in their history and anthropology courses, and they are enthusiastic about collaborating with National Geographic and helping us produce new results that will enhance what we collectively know about Guam and Chamorro history.

But the Genographic Project is foremost a collaboration between participants and scientists, and what we learn from analyzing the DNA is always made available and explained to participants. That is why upon leaving Guam, I promised the Chamorros that I would return to the Marianas next year, present the results, and enroll new participants in this exciting project. And next time I will bring my family. I promised them, too.

Members of the public can participate in the Genographic Project by visiting www.genographic.com.

By Miguel Vilar, Scientific Manager, Genographic Project 

Miguel standing alongside latte stones. Photo by Miguel Vilar.
Miguel standing alongside latte stones. Photo by Miguel Vilar.
Participant swabs his cheek in Mangilao, Guam
Participant swabs his cheek in Mangilao, Guam. Photo by Miguel Vilar.

Learn more:

Europe’s Early Settlers Uncovered

DNA Research Reveals Uros People of Peru and Bolivia to Have Distinctive Genetic Ancestries

Afghans Share Unique Genetic Heritage, DNA Study By The Genographic Project


  1. Johnny Bates Topasna Starnes
    New Port Richey, Florida
    January 9, 2015, 7:28 pm

    My father is John H. Bates a non-Islander Caucasian of Irish/English American descent, my mother a native of Guam USA is Spanish, Carolinian and Taotao. The Ancient people were never called Chamorro until the 1600’s by Filippinos and Spanish mocking the natives. Anyway the Islanders mispronounce the word saying Sa’moro . The Ancients were Taotaomona a Malayo-Polynesian. It is my believe the Jump off point is Harrapan,Cambay, India to Indonesia Southeast Asia Islands. But we Guamanians, wouldn’t surface until the late 1930’s vote to rename from the Sa’moros. (Peli, Kepuha, Taga, Matua & Tongan) are all Malayo-Polynesians of the Area Micronesia. So if you have Filippino, Japanese, Indian, Taiwanese, Chinese welcome to the Austronesian People. We all came from the Empire of the Sun “Mu”.

  2. Mario R. Borja
    San Diego, CA
    August 30, 2014, 11:00 am

    I am leading a group of Chamorros on an epic journey aboard a 47-ft single-hulled sailing outrigger called the sakman that we’ve built here in San Diego. Out journey will begin in Nov 2015 from San Diego to Acapulco then westward to the Marianas following the norther equatorial currents westward. Acapulco is a stop we want to make because of the connection of our islands and people to the Spanish Galleons which may have brought to Guam our ancestors as well. We as a crew would like to be tested as well before the journey begins.

  3. Exequiel V. Borlaza
    Chicago, Illinois
    February 14, 2014, 1:06 pm

    I am Fillipino and l recently learned about our Chamorro cousins from the book of Geographica. Today is my birthday & I was hoping to get my DNA results back to learn more about who I am & who I am connected too. The Genographic Project in Guam will be an additional information for me to know. Please, notify me where I can find & read about the new DNA results in Guam .
    Thank You,

  4. John Francisco
    United States
    January 30, 2014, 7:33 pm

    MY Dad And I Are From Guam And Would Like To Participate In
    The Genographic Project. How Do We Get A Test Kit?

  5. Colleen
    Sinajana, Guam
    January 27, 2014, 5:45 pm

    If I had known they were doing the Geographic Project I would of participated. I just bought a kit for my grandma (whom is completely Chamorro -from what I know based on ancestry starting from 1820s). I’m in the process of mailing her samples out, so let’s see what the results are. I’m quite excited

  6. Carl Peterson
    Tamuning, Guam
    December 16, 2013, 7:38 am

    My wife and I did this 2-3 years ago. You really be surprised to see the map showing where you started and the route you took to get here. Just a hint, we are all cousins!

  7. Adolf Sgambelluri
    Piti, Guam
    December 16, 2013, 3:49 am

    Absolutely an welcomed [project to learn just exactly who we are as a Guamanian. By “ethnicity”…we consider ourselves Chamorros. I tried to explain that the noun Chamorro name is Spanish. The name is replete in South America, especially in Mexico. The vernacular in the language used by locals in Guam, you can split Chamorro to read as in “Cha” meaning belonging to and the reference to “Moro” is considered the Austronesian people blamed for the murder of many American soldiers when they tried to settle on the southern part of the Philippines. So when the Filipino political prisoners were transferred to Guam by both the Spaniards and U.S. government the people on Guam were likened to the “Moros,” added on the “Cha” to form the name Chamorro…people on Guam were compared to the Moros as aggressive and warlike warriors. We the people are so mixed in blood. I come from a family which have the DNA of Filipino, Chinese, Italian, Portuguese, and Spanish. When asked for our race group we obediently place in the form: “Pacific islander.”

  8. J.M. Mendiola
    Camarillo, CA, United States
    December 14, 2013, 6:52 pm

    Would like to participate on the study. My roots are from Rota of Northern Marianas.

  9. Clarice Duenas Perez
    Contra Costa County CA
    December 14, 2013, 9:24 am

    Being of Chamorro descent, I am ever so proud and grateful to hear that National Geographic is sponsoring this study on Guam (“Guahan”), and the growing results are spectacular!

    The Latte Stone(s) is the largest physical identity left to our origin, aside from stone money, several tools and sling stones found across Guam (Guahan). But the latte stone is unique in the “whole wide world”. Be mindful that the smallest island in the chain of the “Marianas Islands”, Rota (“Luta”), our sister island, has the largest quarry of latte stones in the chain of the “Marianas Islands”. Guam (Guahan), by the way is the largest island in that chain of Marianas Islands. Other main islands are Tinian & Saipan.

    My family & I are ever so grateful that our language still exists. Thank you for the hard work the scientists are doing to complete this study on DNA. You’re all so encouraging. Be safe. And yes, Guam is all about family.

  10. D. Perez
    December 13, 2013, 9:39 pm

    If your paternally-inherited DNA project isn’t completed yet, may I suggest that you include older males with indigenous surnames in your study. These males would have the surnames: names with the Tai- and Qui- prefixes, such as Quidachay, Quitugua, Taitano, Taimanglo, etc. These Chamoru men may have more of the distinctive DNA you are looking for.

  11. Erik Maher
    Greenwood Lake, NY
    December 4, 2013, 10:27 pm

    This research is exciting. I’m eager to hear of the results of your study.

    I have a particular interest, as my fiancée’s father and uncle, who are Cebuano and belong to a rare Y haplogroup currently known as D*, have only one 12-marker Y-DNA match out of hundreds of thousands of kits in the database – and that one match is not a fellow Filipino, but rather a man of Chamorro origin who lives in Guam! They have no matches at 25, 37, 67, or 111 markers. The connection with the man in Guam is probably an ancient one.

    My fiancée’s uncle also tested with Geno 2.0 before exporting his results into FTDNA. We’re eager to find other Geno testers who match (closely or distantly). Right now, when you look at his paternal “genetic distance” results on the Genographic website, his DNA point is all alone in a giant sea – not even one single distant match on the outer edge of his circle.

  12. Nate Cordova
    November 17, 2013, 12:46 pm

    Being a former long term resident of the island and my study of anthropology for decades, I am very interested in the study of native Guamanian people, specifically their origins.

    I come from the school of thought that the Chamorros originated from the Philippines. The geography is close, physical appearances are similar, and the Chamorro and Philippines languages show a recent common origin. The Chamorro language would suggest a recent affiliation with the Philippine languages. While it is related to Micronesian languages, their relation is much more distant. If the Marianas was peopled in 2,000 BCE, I do not believe the Chamorro language (minus foreign loan words) is the original language. I would go further and say that a possible second migration about 1,000 to 1,500 occurred to the Marianas based on language similarity.

  13. bette meers
    san francisco, california
    November 1, 2013, 7:55 pm

    This Natl Genographic project just may be the catalyst that convinces us all that we are one world. It is so very exciting!!! Thank you. Bette

  14. JP Leddy
    San Francisco, CA
    October 21, 2013, 1:12 pm

    Is it still possible to be part of the study. I am of Chamorro heritage. Where do I enroll?


  15. Lani Bordallo
    October 19, 2013, 1:14 am

    Thank you, thank you, thank you… for decades my biggest fear of outsiders migrating to our island and the fact that the United States have made themselves at home with no intentions of ever letting go, was going to be the demise of the Chamorro identity. With your mapping our DNA I am thrilled that my fears have been minimized and I can breathe again. I can’t wait for the results. I teach History of Guam at GWHS (the only high school with the largest population of Chamorro kids). If I can ever be of any help to you please do not hesitate to let me know. Si Yu’us Maa’se.
    Lani Bordallo