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Armchair Genealogy

By Melinda Cohenour

DNA: Complex. Tantalizing.
And Nothing Short of Miraculous -
Chapter Two

Last month we embarked upon our in-depth study of DNA, beginning with its history drawing directly from a source online (https://www.dna-worldwide.com/resource/160/history-dna-timeline.) This month we will complete our tracing of the history starting where we left off.



HISTORY OF DNA

1999 - First human chromosome is decoded

History was made when an international team of researchers accomplished the mapping of Chromosome 22 which contained 33.5 MILLION letters (chemical components).
This was a milestone but far from the culmination of the ongoing quest to decode human DNA. As stated in our source online:
"At the time, the sequence was the longest continuous stretch of DNA ever deciphered and assembled. However, it was only the first deciphered chapter of the human genetic instruction book - the rest was still to come."

2000 Genetic code of the fruit fly is decoded

It may seem strange to include the decoding of a fruit fly's DNA among milestones that interest a genealogist; however it was found that the fruit fly's genetic structure is quite similar to that of mammals. Although researchers at the time had achieved the decoding of the most complex organism yet, we can contrast that with the Human Genome Project in this way: every fruit fly cell contains 13,601 genes compared to the 70,000 genes in every human cell!

2002 Mouse is the first mammal to have its genome decoded

"In 2002, scientists took their next big step and decoded the genome of the first mammal the mouse. The achievement allowed them to compare, for the first time, the human genome with that of another mammal. Amazingly, it emerged that 90% of the mouse's genome could be aligned with the corresponding regions on the human genome. Both the mouse and human genome also contained around 30,000 protein-coding genes. These discoveries highlighted for the first time just how closely mammalian species were genetically related."

2003 The Human Genome Project is completed

What an incredible milestone! The observations of Charles Darwin less than 200 years earlier led him to suspect characteristics such as height, eye color, perhaps the very definition of a creature as a horse or pig or human, might be inherited by some unseen organic process. From that first proposed theory, damned at the time as opposing Biblical theories, to the extraordinary news that the international collaboration of geneticists, biologists, and scientists specializing in DNA had completed the sequencing of 99% of the human genome! Following the 2002 announcement the team had accomplished sequencing 90%, work proceeded to fill in the gaps.

"This final form contains 2.85 billion nucleotides, with a predicted error rate of just 1 event in every 100,000 bases sequenced. Surprises included the relatively small number of protein-encoding genes (between 20,000 and 25,000) and that there were similar genes with the same functions present in different species."

One of life's greatest mysteries had been revealed ... with magnificent advances yet to come, perhaps?

2013 DNA Worldwide and Eurofins Forensic discover identical twins have differences in their genetic makeup

Prior to this discovery, it had been assumed monozygotic twins (created by the splitting of one cell) would be truly identical - even to their DNA identity.

" However, the team at DNA Worldwide decided to test this theory by combining Forensic DNA profiling and Genomic Sequencing. The scientists applied ultra-deep, next-generation sequencing and combined this with bioinformatics, sequencing the DNA from sperm samples of two twins and a blood sample of the child of one twin. The Bioinformatic analysis identified five differences (mutations), called Single Nucleotide Polymorphisms (SNPs) present in the twin who was a father and his child, but not in the twin uncle.

"These SNP differences were confirmed by Sanger sequencing and gave experimental evidence for the hypothesis that rare mutations in the genes will occur early, after or before the human blastocyst has split into two and that these mutations will be carried throughout the lifespan."

These findings have a significant impact in cases where legal forensics need to identify the identical twin perpetrating a crime or to resolve paternity issues.

2014 Further Breakthroughs

"Throughout 2014 the world's scientists have continued to develop their understanding of DNA. Researchers announced in May that they had successfully created an organism with an expanded artificial genetic code. This success could eventually lead to the creation of organisms that can produce medicines or industrial products organically.

"There have also been breakthroughs in the medical field; the largest ever study into the genetic basis of mental illness has found more than 100 genes that play a role in the development of schizophrenia. These findings have the potential to kick-start the production of new drugs to treat this not uncommon psychiatric illness.

Geneticists have also made progress in the breakthrough field of epigenetics (the study of changes in organisms caused by altered gene expression). By studying pairs of identical twins, researchers in Sweden have found that changes in the expression of genes involved in inflammation, fat, and glucose metabolism could be behind the development of Type 2 Diabetes."

Future Epigenetics, personalized medicine and greater individual responsibility

The creators of this website have done a marvelous service to those of us not only interested in the study of DNA but who utilize every advancement in our own search for truth:

Who Am I? Who Contributed To My Creation? Where Is The Child I Put Up For Adoption? Who Were The Couple Who Engaged In An Npe (Non-Parental Event) That Resulted In My First Husband Being Abandoned At Birth In The Miami-Dade Orphanage?

These are the issues we, as genealogists or family researchers, are tasked with resolving. The lack of documentation purposely caused by the desire to perhaps provide an adopted child and new family privacy or to protect the reputations of those whose illicit affairs resulted in abandoned children has presented brick walls throughout time. Now we have an incredible tool at our disposal: DNA, Shared Matches, messaging applications, social media ... allowing us to engage long-lost cousins or triangulate DNA Matches with a Common Ancestor in our family trees (always confirm other's research by documenting their profiles).

To wrap up this section, I must provide the creators of this marvelous website their own voice:

"So, what does the future hold for our understanding of genetics? In recent decades, epigenetics has been a ground-breaking area of developing research. Essentially, the term epigenetics means 'on genetics' and refers to the biological markers which influence what 'comes out' of the DNA sequence.

Research has found that there are a huge number of these molecular mechanisms affecting the activity of our genes. Incredibly, it has emerged that our life experiences and choices can change the activity of these mechanisms, resulting in changes in gene expression. Even more fascinating is that these changes in gene expression can be inherited, meaning that the life experiences of your ancestors can fundamentally influence your biological make-up.

These discoveries are likely to have a dramatic impact on the future of the healthcare system. We're beginning to understand that the choices we make can have a long-term impact on our health and can cause genetic level change, which could even impact future generations. Individual responsibility for our lifestyle choices is, therefore, more important than ever before.Another likely future development is the increased use of personalised medicines. Many genetic diseases are caused by mutated genes, but these can differ from one person to the next. By identifying these combinations, medicines can be tailored to the individual, providing the best possible treatment."


Well, good readers, that wraps our review of the History of DNA. This coming month we shall offer a Glossary of terms. This compilation is as much for your author's benefit as for yours. As our title suggests, DNA is a marvelous but COMPLEX subject.

See you next month! In the meantime, continue your research through Armchair Genealogy ... The wonders of the Internet.


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