Daniel runs a podcast in which he discusses 神秘的生物比如大脚怪. He also sets out camera traps in the local forest and goes on expeditions in search of large tracks. 丹尼尔给我们发了邮件, "I collected soil samples from the tracks, and I would love if you could do DNA testing on them."
E-DNA分析
SGS offers DNA testing for various sectors, but the most appropriate technology here involved 环境DNA. E-DNA is the genetic material that organisms shed into the environment. It can be used to identify species in various environments and is ideal for finding elusive and rare animals.
"I was struck by the fact that this 14-year-old had made the link that e-DNA could maybe also be used to find the most elusive creature of them all: Bigfoot,威廉·范·斯特里恩说, 创新经理 SGS全球生物科学中心. "Daniel appeared to be so enthusiastic about the topic and really showed he was embracing science on his quest to get to the bottom of this."
在SGS, we are genuinely passionate about supporting youngsters like Daniel who are dedicated to the pursuit of knowledge and discovery. We therefore decided to support the request, contacted the family and told them we would pick up and analyze the samples at no cost.
那么，我们发现大脚怪了吗?
Well, that unfortunately still remains a mystery!
The samples we received were soil samples with small parts of leaf litter collected from the prints. Our team had to push some of our extraction methods to the limits with the limited volume of the samples. 然而, we did manage to get enough DNA and some solid species detections. We detected Eastern Gray Squirrels and Common Pheasant and also various large mammals like Roe Deer, 野猪, 欧洲獾和 智人 (人类)可能会留下痕迹.
But we also classified some DNA sequences to the family 人科, the taxonomic group to which Humans belong and 猕猴科这是东半球类人猿的一个科. Those last two classifications obviously trigger some speculation…
然而, Vanessa Luis (Chief Molecular Scientist at the GBC) explains, "It is not actually possible to identify Bigfoot via E-DNA without a previous reference in the genetic databases. For that, one needs to have a tissue sample to extract DNA from to then barcode. 不幸的是, no confirmed DNA sequence of Bigfoot exists in the barcode reference databases we use at SGS."
你应该如何解释我们的结果?
作为解释, although detecting the Bigfoot species may not be possible, with E-DNA we can usually match DNA sequences to higher taxonomic levels, 像属或科. We classify our DNA sequences to higher taxonomic levels if we cannot get a species match but have high confidence the DNA sequence belongs to a certain family (group of species).
This happens if reference barcodes do not exist, but also if the DNA we collected from the sample has been degraded and thus no longer matches barcodes in our databases. Sometimes this degraded DNA can also lead to miss annotations and matches with other species or families. This is a key aspect one needs to understand about E-DNA, although some of the risk of degradation can be mitigated during sampling and through sample preservation.
E-DNA is a very powerful tool, but there are some limitations. That's why we make sure that through our reporting we highlight these aspects and mention those taxonomic classification that need to be treated with care.
愿一切都好！!
We are glad we could support Daniel and his friends in his quest for answers and hope it triggers further interest in nature and these exciting technologies. 继续问这些问题!
For further information, please contact:
威廉·范·斯特里恩
创新管理
全球生物科学中心
t: +31882143333
关于SGS
We are SGS – the world’s leading testing, inspection and certification company. We are recognized as the global benchmark for sustainability, quality and integrity. 我们的98,000名员工经营着一个由2万名员工组成的网络,650个办事处和实验室, 共同努力，使一个更好的, 世界更加安全，联系更加紧密.
