Burials show that children with Down Syndrome and Edwards Syndrome were recognized as members of their communities
埋葬地顯示，患有唐氏症(一種與身體許多部位異常有關的染色體疾病，也被稱為21號染色體三體症(Trisomy 21)，及愛德華茲氏症(也被稱為18號染色體三體症(Trisomy 18)，也就是人類第21、18對染色體，出現三處染色體異常情況的兒童，被認定為其群落的成員。
An international team of researchers has analysed the DNA from a world-wide sample of nearly 10,000 ancient individuals to search for cases of Down Syndrome, an uncommon genetic condition caused by the presence of an additional copy of Chromosome 21.
一支國際研究團隊已經分析，來自全球近1萬名古代個體樣本的DNA，以尋找唐氏症病例。這是因21號染色體，存在額外複製物引起的一種罕見遺傳疾病。
Scanning the genome data, researchers from the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) in Leipzig, Germany, found six children with Down Syndrome. Five of these children were buried more than 2,000 years ago and lived to, at most, one year of age.
詳細檢視此些基因體數據，來自德國萊比錫市，馬克斯普朗克演化人類學研究所(MPI-EVA)的研究人員們，發現了六名患有唐氏症的兒童。其中五名兒童於2000多年前被埋葬的，且頂多活到一歲。
Although their lives were short, all of these children received a burial, often with grave goods, showing that they were appreciated as members of their ancient societies.
雖然他們的生命短暫，不過所有這些孩子皆獲得了埋葬。通常具有陪葬品，這表明顯示，作為古代社會的成員，他們是受到重視的。
圖1. 於1989年挖掘活動期間，西班牙納瓦拉自治區阿爾托德拉克魯斯(Alto de la Cruz)考古遺址，早期鐵器時代小聚落的鳥瞰圖。
Aerial view of the Early Iron Age settlement of Alto de la Cruz, Navarra, during the 1989 excavation campaign.
For many years, researchers at MPI-EVA have been collecting and analyzing ancient DNA from humans who lived during the past tens of thousands of years. Analyzing these data has allowed the researchers to trace the movement and mixing of people, and even to uncover ancient pathogens that affected their lives.
多年來，MPI-EVA的研究人員們一直在收集及分析，來自生存於過去數萬年間之人類的古老DNA。分析此些數據，已經使此些研究人員們得以追蹤，人們的遷移及混血，甚至發現影響他們生存的古老病原體。
However, a systematic study of uncommon genetic conditions had not been attempted. One of those uncommon conditions, known as Down Syndrome, affects nowadays around one in 1,000 births.
不過，一直未曾嘗試有關罕見遺傳疾病的系統性研究。那些罕見疾病之一，被通稱為唐氏症，當今影響大約千分之一的新生兒。
To their surprise, Adam “Ben” Rohrlach and colleagues identified six individuals with an unusually high number of DNA sequences from Chromosome 21 that could only be explained by an additional copy of Chromosome 21. One case from a church graveyard in Finland was dated to the 17th to 18th century.
令他們驚訝的是，Adam“Ben”Rohrlach及其同僚確認了，6個個體的21號染色體具有，來自僅能由21號染色體額外複製物，來作出解釋之21號染色體異常多的DNA序列數量。來自芬蘭一座教堂墓地的一個實例，被追溯到17至18 世紀。
The remaining five individuals were much older: dating to between 5,000 and 2,500 years before present, they were found at Bronze Age sites in Greece and Bulgaria, and Iron Age sites in Spain. In all cases, the researchers were able to obtain a wealth of additional information about the remains and the burials.
其餘五個個體較古老得多：追溯到距今5千至2千5百年前，他們是在希臘及保加利亞的青銅時代遺址，及西班牙的鐵器時代遺址中，被發現的。在所有實例中，此些研究人員皆能獲得，有關此些遺骸與埋葬處的大量額外資訊。
圖2. 一名在出生時或出生前不久死亡，被埋葬在阿爾托德拉克魯斯之CRU001男孩個體的遺骸。
Remains of individual “CRU001”, a boy who died at or shortly before birth and was buried in Alto de la Cruz.
While individuals with Down Syndrome can live a long life today, often with the help of modern medicine, this was not the case in the past. Indeed, age estimates from skeletal remains showed that all six individuals died at a very young age, with only one child reaching around one year of age.
儘管具有唐氏症的患者們，在現代醫學的幫助下，目前能長時間存活。不過，於過去並非此情況。事實上，從骨骼遺骸的年齡估算顯示了，所有六個個體皆於很小的年齡就死亡，僅有一名小孩達到大約一歲。
The five prehistoric burials were all located within settlements and in some cases accompanied by special items such as coloured bead necklaces, bronze rings or sea-shells. “These burials seem to show us that these individuals were cared for and appreciated as part of their ancient societies,” says Rohrlach, the lead author of the study.
五處史前埋葬處均位於小聚落內，在某些實例中，伴隨有諸如彩色珠項鍊、青銅戒指或貝殼等，特殊物品。該項研究首要撰文人，Rohrlach宣稱：「此些埋葬處似乎向我們顯示，這些個體身為其古代社會的一部分，受到了呵護及重視。」
Although the study was aimed at finding cases of Down Syndrome, the researchers also discovered an individual with a different condition. Among the approximately 10,000 tested DNA samples, one individual had an unexpectedly high fraction of ancient DNA sequences from Chromosome 18 that showed that she carried three copies of this chromosome.
雖然該項研究旨在尋找唐氏症病例，不過此些研究人員也發現了，一個罹患不同疾病的個體。在大約1萬個經測試的DNA樣本中，有個個體來自18號染色體具有，經證實顯示，她具有該染色體三份複製物，意想不到之高比率的古代DNA序列。
Three copies of Chromosome 18 are known to cause Edwards Syndrome, a condition associated with more severe health issues than Down syndrome. With an incidence of less than one case in 3,000 births, Edwards Syndrome also occurs much less often than Down Syndrome.
18號染色體的三份複製物，已知導致愛德華茲氏症。這是一種與，比唐氏症更有嚴重健康問題，有關聯的疾病。具有3千名新生兒中，不及一例的發生率。愛德華茲氏症也比唐氏症，更少常發生得多。
This find, too, was made at one of the Spanish Iron Age sites, leaving the researchers with a mystery to solve.
此發現，也在西班牙鐵器時代的遺址之一被發現。這給此些研究人員留下了一個，有待解開的謎團。
“At the moment, we cannot say why we find so many cases at these sites,” says Roberto Risch, an archaeologist of the Universitat Autònoma de Barcelona working on intramural funerary rites, “but we know that they belonged to the few children who received the privilege to be buried inside the houses after death. This already is a hint that they were perceived as special babies.”
西班牙巴塞隆納自治大學，針對壁內埋葬儀式進行研究的考古學家，Roberto Risch宣稱：「目前，我們無法說明，為什麼在此些遺址，我們發現如此多的病例。不過我們知道，他們屬於少數獲得特別待遇，在死後被埋於建物裡的孩子。這已經是一種，他們被意識到是特殊嬰兒的線索。」
As the number of DNA samples from ancient individuals continues to increase, the authors plan to further expand their research in the future. “What we would like to learn is how ancient societies reacted to individuals that may have needed a helping hand or were simply a bit different,” says Kay Prüfer, who coordinated the sequence analysis.
由於來自古代個體之DNA樣本數量不斷增加，此些撰文者們計劃，於未來，進一步擴大他們的研究。協調該項序列分析的Kay Prüfer宣稱：「我們想獲悉的是，古代社會如何對可能曾需要援手或只是有點不同的個體，作出反應。」
網址：https://www.mpg.de/21538858/0213-evan-ancient-genomes-reveal-down-syndrome-in-past-societies-150495-x?c=2249
翻譯：許東榮
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