The book "The DNA Guide for Adoptees" currently available on Amazon for Kindle preorders is nearing publication! On May 30th, readers can find it on Kindle and in print in a paperback version. My co-author Shannon and I are busily preparing to be ready for reader questions and comments and are planning genealogy and genetics conference booth appearances in the summer and fall.
What’s the difference between a first cousin, a first cousin, once removed and a second cousin? I get this question a lot! I usually end up explaining it at least once during Thanksgiving dinner each year.
Cousins who share a set of grandparents because their parents are full siblings are first cousins.
Cousins who share one grandparent because their parents are half siblings are half-first-cousins.
Cousins who share a set of great-grandparents because their parents are first cousins and their grandparents are siblings are second cousins.
“Removed” comes in when the two people in questions are from different generations.
Did you know that by textbook definition, full siblings (brothers and sisters who share a common mother AND father) are supposed to have about 50% of their DNA in common? From projects like the crowd-sourced data collection project by DNA Central founder Blaine Bettinger — The Shared cM Project explained well in this post by Leah Larkin — we have learned that human biology doesn’t always follow the rules!
Genealogists are a creative bunch, and I love to read about the information they discover and record about family. Some genealogists track down death certificates and record the official cause of death for ancestors. Others learn medical history from living relatives and write that down. I quietly applaud when I read about someone finding and saving medical information on ancestors and relatives like this!
As a genetic counselor and genealogist, family medical history will always be an important in my eyes. This information is difficult to retrieve once relatives pass away.
There is a lot of misinformation spreading online about a gene all of us have called MTHFR. (We each have two copies it, actually: one from mom and one from dad.)
Self Magazine published an article this week specifically addressing the MTHFR gene and all the facts we know about it. It was written by Tara C. Smith, a person with a PhD in epidemiology. Epidemiology is the study of how different factors influence the health of people, and those with a PhD are trained to understand the outcome of studies at both the group level (large populations) and at the individual level (YOU!).
I read this article yesterday and feel like it is the BEST ARTICLE to date on MTHFR. It will be accessible to most readers, no matter your level of knowledge about DNA or genetics research.
One by one, women have begun to reach out to me. They describe a similar scenario.
Their husbands were unaware they had fathered a child in the past (typically, it's a daughter).
That child is now an adult.
Consumer DNA testing helped reunite the adult child with their father.
These situations involve a lot of emotions for everyone, including the adult child, the father, his wife/significant other, and other children in the family.
23andMe released a new health report this week, and it's quite a bit different from the other types of reports they've released in the past.
Most conditions that affect people (like type 2 diabetes) are complex in origin, meaning that even if it's "genetic," it's not necessarily easily-tested by DNA. This is due to reasons such as polygenic factors being influenced by environmental factors (diet, smoking, exercise, etc.). Polygenic refers to the fact that there can be dozens - if not hundreds or THOUSANDS - of genetic factors involved, each one having only a tiny impact on overall risk.
This is what you'll eventually see if you keep scrolling down your 23andMe report, and it's important to read and understand these things before you take anything away from your diabetes risk as reported by 23andMe. It’s important to know what a DNA test can’t tell you, as much as what it can.
Interested in reading more about this topic?
This article in MIT Technology Review brings some good points to the discussion.
This article by Jeanette McCarthy on Precision Medicine Advisors reviews polygenic risk scores, including a section on why they are controversial and not everyone agrees they are ready for prime time.
This article on the International Society of Genetic Genealogy wiki gives a good introduction to polygenic risks scores as well and is written by a PRS researcher.
If you are looking for a licensed and certified genetic counselor’s help in understanding your report, reach out or schedule with me. I’ll be happy to go through it and answer your questions!
Nearly a year ago, the genealogy/DNA testing company MyHeritage announced the roll-out of a program they call DNA Quest. They asked me to be part of the volunteer advisory board for this project, a program aimed to take down the barrier of DNA test cost to searching adoptees and the birth family members searching for them. Last week at a genealogy conference called RootsTech, MyHeritage announced an extension of DNA Quest to provide free testing to an additional 5,000 participants. Share the news with family and friends who you think may be interested!
The New England Journal of Medicine recently released a paper on an extremely rare set of boy/girl sesquizygotic twins. Early in the pregnancy, it was noted on ultrasound that the twins shared a placenta, indicating they were likely identical twins. Sesquizygotic twins have been reported in the literature before, but this is reportedly the first case of it being detected during a pregnancy.
Heart Disease and why DNA matters
Genes involved in the function of our cardiovascular system differ, ranging from those involved in the structure of the heart, the shape and density of the muscle cells and connective tissues, and even the function of the cells involved in electrical signals that tell the heart to pump. Genes can even influence how much cholesterol our bodies create. (You read that right! Not all cholesterol comes from our food!).
Valentine’s Day has come and gone, but it doesn’t mean we stop talking about hearts! February is Heart Month, which makes it a perfect time to discuss heart health and how genetic counseling and DNA testing might help you understand your chance of heart disease.
Helping everyone get connected to reliable information to understand DNA testing - whether for ancestry purposes or medical - is a central goal of my blog, so I’m taking a detour from my recent posts on family matching surprises to visit this DNA health topic. This posts kicks off a three-part series on DNA and heart health. Part one will cover the basics before we dive further into genetic counseling and at-home tests and third party reports that give information related to cardiovascular issues.
Our genetics can contribute to a chance for heart issues, but it’s not the only factor. Read on to learn more!
If you are a parent of a child who was conceived with a donor egg or sperm and they do not yet know it, the time to be proactive is now. Consumer DNA tests like 23andMe and AncestryDNA are changing the way people discover their genetic origins, and this new reality has implications for many people, including those who have kept the secret of donor conception hidden from their children.