A new look at Ozti the Iceman's DNA reveals new ancestry and other surprises

A new look at Ozti the Iceman's DNA reveals new ancestry 

and other surprises 

A new analysis of the Iceman's DNA, a 5,300-year-old mummy found in the Tyrolean Alps, challenges previous assumptions about his ancestry. Scientists had initially suggested that his ancestors came from the Caspian steppe, but this new research indicates that the steppe ancestry is entirely absent. Instead, about 90 percent of the Iceman's genetic heritage is traced back to Neolithic farmers, which is an unusually high proportion compared to other Copper Age remains. The study also reveals that the Iceman had male-pattern baldness and much darker skin than previously believed. This finding highlights that genetic changes for lighter skin tones in Europe occurred much later in human history, with the majority of people in Europe between 40,000 and 8,000 years ago having skin as dark as people in Africa.

This article just gives us another example of how many question marks we have in genetics. There are so many unanswered questions that leave us in the dark. There is a significant time period of ancestry missing between a few hundred years. There is always more work to be done in the field of genetics with all the research and data we can get together to eventually fill the gaps we have.

LINKS:

https://www.sciencenews.org/article/new-otzi-iceman-dna-ancestry-genome

https://www.scientificamerican.com/article/oetzi-the-iceman-gets-a-new-looks-from-genetic-analysis/

4,000 Year Old Egyptian Mummies Thought To Be Brothers

Coffins of two mummies who may be brothers are displayed in the Manchester Museum. Some anticipated the thought of the two mummies being brothers for many reasons. Scholars pointed out that the anatomy of the skulls were different and researchers began studying scraps of their skins. From this information, researchers concluded that their complexions revealed that they do not share parents. Genetic studies are being tested to help determine if these conclusions are true. The researchers began to analyze DNA and have also dug deeper into the mummies Y chromosome, which were inherited from their father. The DNA results showed that complete mitochondrial profiles have been recovered, therefore making them being able to say confidently that they are maternally related. According to an article on News Week, "The researchers say that the different treatments of mothers and fathers in the inscriptions suggest that maternal heritage was more important to the ancient Egyptians than paternal heritage was." I found this article interesting because I think that it is cool that there is technology out there to be able to help researchers trace back ancestry. Even including mummies, that is something that always seemed interesting to me throughout history.

How Old is Smallpox Really?

     According to research by an international team of researchers Smallpox might have merged way later then we previously thought. Tissue samples were taken from a Lithuanian child mummy that us dated back to the 1600's. It was concluded that the cause of death was smallpox, but not exactly the strain we cause just a hundred years ago. Reconstructing the full RNA sequence of the smallpox virus strain and compared the results to more recent samples. With this information the team was able to make a time line of the smallpox virus and piece together information about the different strands. While looking at the timeline for the diseases the rate of mutations was also studied and their was found to be two major strand groups, and all related back to a simple common ancestor.  With the information uncovered about the common ancestor it was evaluated that smallpox must have not always been such an epidemic. If small pox had been an epidemic for the thousands of years that it has been around researchers would not have been able to find a common ancestor since it would have diverged tremendously over time. 

     This article is extremely fascinating because with a small sample from a mummy that is thousands of years old they were able to make a time line for small pox and better understand how the virus grew and mutated. With more data like this hopefully we can come to better understand how viruses are spreading so rapidly and diverging out of nowhere. With this knowledge we can better understand and develop more vaccines and save thousands of lives.  

For more information on the history of smallpox go to - https://www.cdc.gov/smallpox/history/history.html

Main article: http://blogs.discovermagazine.com/d-brief/2016/12/08/child-mummy-smallpox-timeline/#.WQfiYIn5601 

Child Mummy Could Rewrite Smallpox Timeline

     This article  explains how a young mummy girl named Lithuanian who holds the oldest sample of smallpox. The tissue sample that was taken from Lithuanian that dates back to the 1600's gave researchers the ability to reconstruct the RNA sequence for the smallpox virus. The international researchers took the reconstructed RNA and compared its genetic samples with recent samples. By comparing the strands researchers were then able to create a phylogenetic tree that traced the history of the virus. By creating the phylogenetic tree researchers then tried to take the time back to measure its rate of mutation in order to understand the pace at which the virus grows and spreads. By examining the old strand further the researchers were able to identify that the common strand shared a common ancestry.
     I found this article useful in understanding the life span of the small pox. The small pox was a big epidemic that happened in Europe and it was not until the first vaccination came about that the smallpox was kept under control. It is important to understand were the strain came from and how it has changed over time in order to see how the strand evolved. In order to prevent a future small pox epidemic it is useful to understand its make up in order for this epidemic to not happen again.

RNA Used in Sequencing Ancient DNA

A Peruvian Mummy 

            Oftentimes, when ancient samples of DNA are taken, they have inhabited warm soil and are contaminated by bacteria (unlike the pure samples of hair, tooth, or bone that had been preserved in frozen ice or soil). Less than 1% of human DNA (which is often short and degraded) is found in these samples.  The techniques that exist, such as zooming in on the DNA or filtering the sample using modern DNA that are similar to the sample sequence, are costly and only expose some of the genome. At the American Society of Human Genetics, a technique using RNA to purify the ancient DNA was reported. At Stanford University, a team has found a “cheap” way to create RNA sequences that are close to the sample DNA sequence. The RNA probes can analyze a whole genome at a low cost, only $50 per sample (saving about $300,000).

            RNA probes attach to beads and the nonhuman DNA is washed away when the probes and DNA sample are mixed. Then, the probe is removed by an RNA-chewing enzyme. Finally, the pure DNA goes through the genome sequencing machine. Two to thirteen times more genetic sequence was recovered (as compared to just sequencing) when using this method on 500 to 3500 year old samples from teeth, hair, and bone.

            Thus far, the technique has already proven that a Peruvian mummy was not of European descent, as previously believed. Currently, it is being used to study ancient dog DNA to understand dog domestication. The technique may also prove helpful for microbial genomics researchers (to rid samples of human DNA) and forensics (when dealing with human DNA with unwanted bacteria).

            Similarly, researchers in Germany were able to sequence an archaic Siberian girl’s genome. The new technique using the amplification of small DNA strands. An enzyme copies the sequence of one strand of DNA. The genome was sequenced thirty-one times. The genome of the girl more than 50,000 years old was as clear as a sequence of a living person’s genome.

            I found that the revelations of “RNA Helps Resurrect Ancient DNA” were fascinating.  When I learned that we are able to have our entire genome sequenced, I was riveted. To learn that scientists can sequence the genome of DNA from thousands of years ago is even more captivating! I was surprised to read that the technique of using RNA to purify DNA is so effective, that it is able to sequence from samples that have less than 1% of DNA. Further, I was amazed by the fact that it costs a mere $50. The fact that we are able to know such a great deal about our ancestors captivates me and stimulates my interest to see what these techniques can teach us. 

Primary Article: http://www.sciencemag.org/content/342/6158/543.full

Secondary Article: http://www.sciencemag.org/content/337/6098/1028.full?sid=5bb97fdf-27a3-41b8-bf1e-89a3fd5ab007

Otzi the ice mummy's secrets found in DNA

Otzi is a mummy which was found in 1991 on an Alpine glacier between Austria and Italy and dates back 5300 years ago. Albert Zink from the Institute for Mummies and the Iceman in Bolzano, Italy have extracted and analysed DNA which was extracted from Otzi's pelvis to help figure out more about his life. The findings concluded that his descendants live on the Mediterranean islands of Corsica and Sardinia, that he had brown eyes and hair, and was lactose intolerant. The way that they were able to tell that he was lactose intolerant was because of the fact that he had a mutation to his MCM6 gene which indicates he could not digest the lactose sugar in milk. Another finding was that he would have probably developed heart disease because of a genetic mutation that he carried increases the risk of coronary heart disease by 40 percent in modern humans and two other mutations that made him prone to a build up of fat in the linings of his arteries. To support this, earlier investigations showed that his major arteries and aorta were calcified. To establish his closest living kin by comparing to DNA of 1300 Europeans, 125 North Africans, and 20 people from the Arab peninsula and determined his kin was found on Sardinia and Corsica.