Our genes (the DNA coding we received from our biological parents at birth) imbue us with a vast set of "possibilities" as we develop physically, intellectually, emotionally (and, perhaps, even spiritually). This sequencing of genes is called our genotype and is instrumental in determining our hair color, our facial features, length of our our second toe, our psychological dispositions, etc. These inherited features are known as our genotype.
Our phenotype is a far different us. It's the us that actually emerges as we develop, the us that others come to know as us. Phenotype is the us that results from the interplay between our genetic coding and our life experiences. Phenotype influences stuff like whether we like to dance or not, what our food preferences are, how we deal with conflict, how much and what we read, our IQ, etc.
Turns out that a lot of those life experiences (both those that happen outside of our control and those within our control) seem to "turn on" or "turn off" many of the genes we are born with. Yep, it is increasingly obvious that the genes are not so much like rules chiseled in granite as they are on-off switches that control possibilities of manifested traits. Wow! (This is now commonly referred to as the study of epigenetics.)
So what? you may be asking. Here's what: There are great and increasing implications for our personal growth and malleability as we learn more about genes, the way they get "expressed" in our lives, and our ability to influence their on/off status. Very cool!
It seems we have great power to influence who we become. That's intriguing, and heartening, and a little bit frightening. Begs the question: Who do I really want to be? (Because I might actually be able to make that person "happen").