This was posted on reddit and while I have no actual proof the situation is accurate, here is the title of his thread.
“My dad’s index tip was cut off when he was 10, my index is shorter than my pinky.”
Here is the picture he put up as proof.
How could a “short index finger” trait be passed down via genes if the Dad only lost the tip through an accident?
Explain for me, please. Or at least reveal I am a moron for even considering this. 
Genetics don’t work like that. Cutting off a finger does not modify DNA to add a “short finger trait.”
Ask Lamarck or Lysenko.
But scientifically it’s nonsense.
Consider: despite 5000 years of tradition, Jewish boys are born with foreskins.
You are a moron for even considering this.
This is Lamarckism, “the hypothesis that an organism can pass on characteristics that it has acquired during its lifetime to its offspring. It is also known as the inheritance of acquired characteristics or soft inheritance.”
Despite scientists searching for good evidence of this for the past 200 years, none has been found.
So, with seven billion people in the world are the chances that a finger shortening like this could just be coincidence good? Sure. There are plenty of threads here on amazing coincidences. This is another.
Weird coincidental mutation, or photoshop.
That’s not just a short finger, he’s missing a whole bone in the middle! Looks like a bad photoshop job to me.
Also I would not rule out Photoshop. Could also be an astounding coincidence although I am very suspicious about a shortened finger than has otherwise normal proportions.
Moderator Warning
You’ve been around plenty long enough to know that insults are not permitted in General Questions, no matter how dumb you think a question is. This is an official warning for insults.
Colibri
General Questions Moderator
It was a joke. The OP said “explain for me, please. Or at least reveal I am a moron for even considering this.” I protest this.
While injuries like that described in the OP can’t be passed down, recent evidence has indicated that some acquired characteristics can be passed between generations by the mechanism of epigenetic inheritance. This involves methylation of the DNA that alters gene expression, but not the actual gene.
I really think you should have quoted that part of the OP in your reply. To anyone who missed it, yours really does look like a warnable insult.
He asked for an explanation; all you provided was an insult. The warning stands. If you want to dispute it, take it to ATMB.
Apparently if we read far enough into the comment section, we learn that his mother has weird fingers and that genetic trait has been passed down to him. So, yes, I was dumb to even let this linger in my mind.
I don’t know why I considered it for even a second.
Epigenetics is an interesting discovery. But it doesn’t alter the basic fact that you can’t pass on any genes to your children that you weren’t born with (barring mutations in a sperm or egg cell).
Right. And unlike genes, epigenetic changes are not passed down indefinitely; they eventually disappear.
also the short finger is on the wrong hand.
I figured someone would raise epigenetics as a nitpick. But it’s so irrelevant to this particular example that I decided not to mention it myself and just point and laugh at poster who brought it up.
You win.
Heh. Back in 1979, I answered a newspaper ad seeking a roomie for a 2-BR apartment (Irrelevant spoiler alert: I passed the interview and got the room). My new roommate, Howie, was missing the first joint of the index finger on his right hand.
Several months later, the holidays came around, and Howie’s dad came out to SoCal to visit. Oddly enough, he ALSO had no first joint on his right index finger! Genetics?
Nope. See, Howie and his dad were both from Wisconsin, and they had both put in their time working in the agricultural field. And they had both lost their phalanges in farmwork-related accidents.
Hey, if not for nitpicks this thread could have ended after the second post.