Kansas Snapshots by Gloria Freeland - March 4, 2022
Who are you?
An hour into our first date almost 35 years ago, future husband Art and I discovered we shared an interest in family history.
Mine was largely boxes of family photos, letters and other artifacts, while his was primarily information gathered from old
newspapers, courthouses and libraries. We were oddballs, as it was a hobby few engaged in.
But a fire had already been lit 10 years earlier by the television show "Roots." Interest accelerated with the blossoming of access to the internet and personal computers, making gathering and organizing information easier and less time-consuming. By 2014, the Time.com website quoted ABC news sources as stating, " ... genealogy is the second most popular hobby in the U.S. after gardening ... and the second most visited category of websites, after pornography." It seemed we had moved from oddball to mainstream.
Until recently, the changes were focused squarely on easier and quicker access to existing records. The first tool that could be called something new was DNA testing - and it has exploded! The Massachusetts Institute of Technology estimated that, as of last year, 100 million people had spit into tubes or swabbed their cheeks to get samples which, when analyzed, would tell them their family origins. The public's familiarity with DNA�s application to crime investigation influenced the public perception of the science. It seemed what had once taken a lifetime to discover could be had for around $100 and a few weeks' wait.
But reality didn't match expectations. Two sisters who sent in samples and received different reports immediately wondered if there had been an error or perhaps they weren't really sisters. The problem was they, like many others, didn't understand what such tests can and cannot do.
Humans have 23 pairs of chromosomes - 46 total - in almost every cell of their body. Each is a thin chemical strand - DNA - that controls cell operations and physically makes us who we are.
Our sex cells are the oddballs, containing only one of each pair. When a baby is conceived, the 23 from mom's egg and the 23 from dad's sperm combine so the baby has the required 46. As is typical, the two sisters simply didn't get the same halves.
As a child grows, the replication of DNA in new cells isn�t flawless. These mutations - "mistakes" here and there - usually have no effect because only about one percent of our DNA plays a role in cell operations. Some refer to the remaining 99 percent as "genetic junk."
Within that critical one percent, some mutations produce effects such as different eye and hair colors. Others might make a person smarter, stronger, have a better immune system ... or be fatal.
Non-fatal mutations accumulate over the centuries making everyone's DNA different. A particular difference can be found in their offsprings' DNA IF it is part of the 50 percent they received from the parent.
Since a child gets only 23 chromosomes from each parent, is it possible those 23 came from only one grandparent? It's possible, but unlikely. When sex cells are made, about half the time, portions of the pairs swap DNA, making many of the chromosomes in a sex cell a hybrid of the parents' chromosomes. However, over the course of about 10 generations - about 250 years - the DNA of some of the people we call ancestors will, on average, be completely lost - we will have none of their DNA! A person alive today may be a descendant of a passenger on the Mayflower, but not share any common DNA with them!
So-called identical siblings are the result of a chance event in the womb. While the embryo is still only a few cells, it separates into two or more pieces. Once they lose touch with each other, each group replaces the missing part, eventually yielding two or more offspring with identical DNA.
Since every cell division opens the door to a mutation, the cells of "identical" siblings will also differ to a degree.
For peoples who historically didn't travel much or tended to marry within the same group, mutations within the group tended to also remain within it. So when a living person's DNA sample contains one of these mutations, it is quite likely the person had an ancestor from that group. This is how a testing company predicts what percentage Irish, Ashkenazi Jew or sub-Saharan African a person is. But these are likelihoods, not certainties, and depend on what degree of similarity the person has with the people in the company's database.
European folks and their descendants have been into genealogy for some time, but Africans, Asians and Latin Americans not so much, making the database portions for those regions less reliable. In addition, companies like 23andme and Ancestry have different and continually-expanding databases. With different pools of data and different criteria for what constitutes a match, origin reports will be somewhat different.
If a sample submitter agrees to allow his or her DNA profile to be searched by others, a connection with a distant relative may be found and the amount of common DNA will provide guidance on what the closeness of the relationship is. For example: a child gets exactly half its DNA from each parent. A parent's sibling, on average, shares half, so that child and the aunt or uncle typically share a quarter of their DNA. A child of the aunt or uncle also only receives half, so first cousins will usually share one eighth of their DNA. But the same results will occur between a child and an aunt or uncle if the parent and the aunt or uncle are only half siblings.
If someone just wants to know his or her general origins, the $100 DNA test will fill the bill. But it won't provide the names of ancestors or the precise locations of where they lived. That is why sites like Ancestry.com continue to accumulate public records.
Old-fashioned techniques, perhaps augmented by DNA testing, are the only way to answer the question, "Who are you?"
Top-left: Daughter Katie and hubby with DNA sample "spit tubes;" top-right: daughter Mariya and her results, indicating she is exclusively northern European; bottom-left: chromosome photo with pairs arranged from longest-to-shortest. The 23rd pair determines if a person is male or female. The long one is called "X" and the short one "Y." A female has two Xs while a male has one X and one Y; bottom-middle: "chromosome painting" where segments have been color coded by identifiable groups, such as Irish. The greater variety of colors indicate a more varied genetic background and many shorter segments indicate the variations began further back in time; bottom-right: a female with far less genetic diversity than the male and whose ancestors began to mix far more recently. (Bottom images from 23andme.com website.)