It’s funny how we tend to find patterns in things. Left alone, we tend to gather, order, and number everything we can. Take the stars in the sky. Or the stock market. Even gambling. I loved it when I talked to my parents after an academic trip overseas. Here’s how it would start: “How long was the flight? How many days were you there? How many places did you visit? How many people live there?” Pattern recognition probably began as a survival skill, but now numbers and patterns are a way to keep our world a more familiar, and less overwhelming, place to live.
A Line for All Times
Guilty of the same behavior, I noticed a pattern in the research that I presented in a lecture entitled “The Skinny on Advanced Paternal Age,” at the Integrative Fertility Symposium in Vancouver. The pattern was a curved line, a shape like a hockey stick on its side with the blade facing up.
The first time the “hockey stick” curve came up was when we discussed how the prevalence of chromosomal abnormalities in offspring of women changes with age. It’s pretty much a straight line rising slowly from maternal ages 21-35 years and then takes a sharp turn upward after that. This curve is the benchmark hockey stick curve in the field, familiar to all of us for years.
Get in Line
The second time that curve shape came up was as I reviewed what happens to sperm DNA integrity with paternal age. Called DNA fragmentation, this issue can impair a man’s natural fertility potential and result in higher miscarriage rates among partners and may even impair the ability of vitro fertilization (IVF) to do its job. That curves also looks like a straight line with a slight upward slope up to 60 years or so, and the takes a real bend upward after that. Different issue, different sexes, same curve.
The third time the hockey stick showed up was during a review of how single gene mutations in offspring change with paternal age. These genetic aberrations result in conditions in offspring like dwarfism, progeria, marfan’s, hemophilia and retinoblastoma, among others. This curve starts out straight with a slow, even rise until age 60 years of age, after which it also heads north.
Stay in Line
Does it mean anything that these curves look so similar? Who knows! The conditions they represent are genetic and all increase with reproductive age. However, they represent different genetic processes that may have nothing to do with each other.
Or do they?
My hunch is that these curves are similar not by chance, but for some biological reason yet unknown. At least in men, maybe the genetics represented by these curves are linked in some fundamental way. And because I am guilty of ordering chaos, I have a funny feeling that this same curve will appear again as we discover how sperm epigenetics changes as men age. In the words of Albert Einstein: “Look deep into nature, and you will understand everything better.”