Apples Don't Fall Far From the Tree

Source:  Apples Don't Fall Far From the Tree    Tag:  is red hair a recessive gene
Chart of the Weasley, Potter, Malfoy, and Scamander families,
courtesy of Harry Potter Lexicon


Where did you get that red hair?

One kid I knew growing up was taught to say "from the mailman" in response to that question, because neither of his parents had red hair. But there were relatives in their extended family tree with the same phenotype - red hair and blue eyes - indicating that those recessive traits were being carried throughout the generations, but waiting to be matched with other recessive genes in order to become apparent. Because the truth of the matter is that we are all genetic combinations of our parents, grandparents, and beyond - combinations that result in physical traits that are recognizable from generation to generation.  But what lies beneath the surface - our health traits - is just as easy to spot if we think about it.

Therefore, today's HealthTwisty comes with an assignment: create a family tree. Not just one with names and dates of births and deaths, but one that includes all the health and occupational information you can mine from your family. These intergenerational facts are actually clues to your own health and can provide a road map on how to protect or enhance it.

If you've poked around HealthTwisty for awhile, you know that personal genetics or susceptibilities are the basis of much of the information here. Choices about food and our environments can work for or against our basic genetic make up, so it is important to know the genetic hand we are dealt. After all, we can't change our genetics (yet). But we can change our environments.

To get started, here are some things I'd include in a family medical history:
  • names, gender, dates of birth and death of first and second-degree family members.
  • causes of death.
  • known illnesses, allergies, and conditions, such as cancers, a penicillin allergy, arthritis, or infertility.
  • mental health issues, such as depression, addiction, or alcoholism.
  • inborn genetic issues, such as Downs syndrome or cystic fibrosis. 
  • learning issues, such as dyslexia.
  • unusual family traits, such as eyes that are different colors, premature greying, or a shock of white hair, all of which could signify underlying conditions.
  • occupations, which could account for or contribute to some diseases.
  • place of residence, such as a farm, an urban setting, or the suburbs.
  • anything else of interest.
This exercise is just a riff on what a good family physician asks about during a comprehensive exam. In recognition of the basic importance of knowing one's family history, CDC offers a  computer program where family members can record and share their histories. CDC even has a campaign running in this season of family reunions that encourages people to seek health information while they are gathered together. While researching resources, I found out that the US Surgeon General has declared every Thanksgiving since 2004 as "National Family History Day" for this exact purpose. Who knew?

It's an interesting exercise. I've done a medical history for my grandparents and parents and my husband's parents and what we know of his grandparents, as well as for my husband and myself. By mapping it out, I was reassured that for the most part, both sides of my family and one branch of my husband's family generally live into their 90s in reasonably good health. But we have a lot to watch out for: different branches of our families have autoimmune diseases, cardiovascular disease, or eye problems like macular degeneration and glaucoma. Because so many of those conditions  have things you can control (like body weight to prevent diabetes) or can be screened for in order to facilitate early treatment, there are measures we can take to minimize our risks of developing them or to catch them early if they do occur.

Of course, the way genes combine is not always straightforward, which means that biology does not always equal destiny. In other words, just because one of your parents developed cancer does not mean you will. The concept of how complicated genetics can become was brought home to me years ago when I attended and wrote the report for  a conference on sex and gene expression. This extremely technical conference focused on the differences in development and disease by sex and in the ways genes can be expressed. One interesting aspect called crossing-over occurs during the meiotic phase of cell division. The end result of this process is that we inherit large chunks of DNA from our grandparents. Therefore, examining your grandparents' traits may be as important as your parents' in determining your genetic make up.

Further, it is established that diseases such cancers need a series of mutational hits to form, so merely the presence of a genetic mutation that puts you at higher risk does not mean a cancer will develop.  This is why it is important to consider the environmental aspects of family members' diseases. For example, if you have a grandfather who died from lung cancer, it would be good to know if he smoked, if he worked in the construction industry where he may have been exposed to asbestos, or if he was a lawyer exposed to nothing more harmful than fumes from the copy machine. If he smoked or worked with asbestos, chances are those external factors caused his lung cancer and therefore you are not at increased risk of developing it (as long as you don't smoke or work with asbestos!).

This type of observation costs nothing more than your time spent in putting it together. You can also opt to spend some money and purchase a personalized genetic test. For about $100-$500, you can find out risk factors for certain diseases, the presence of carrying a heritable disease, and how you might react to certain drugs.

For the most part, these tests tell you that you may have the genetic makeup that predisposes you to something, but can only provide a relative chance that disease will actually develop unless the disease is a genetically dominant, like Huntington's Disease. Further, there are many steps involved in gene expression that are not captured by a recitation of the base pairs.  However, overall, these tests can be very useful - especially if you don't have information on your birth family.

Making a family history of health is not a quick process. Many people only remember what relatives died from, but not illnesses or conditions for which they may have been treated during their life. Or they may not think it important to recall that Grandpa Joe immigrated from an impoverished country where he was malnourished during his early years - a factor that could help explain his short stature and weak bones. So some probing and detective work may be required. Even only mapping your immediate family can be beneficial and may provide information to better manage your health. If you have kids, giving them a family health history can be important, not only for their current health, but in the future as the field of genetics advances in great strides.

In honor of the final Harry Potter movie, I chose the illustration at the top of this article that maps out the family trees of some of the most well-known wizards of our time. But there's nothing magic about genetics (even though there are surprises, like red hair popping up every now and then) and making a family health history can take away some of the mystery behind illnesses or just plain not feeling as well as we should. Using these clues to make sense of our own health and adjusting our environments accordingly is something even us Muggles can get behind!

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