Download Genetic Advice Question: A close friend confides in you that he

Genetic Advice
Question:
A close friend confides in you that he thinks that one of "his" children is not
his. When pressed for details he points out to you that both he and his wife have
dark brown hair and that his baby has blonde hair. In the conversation he adds
that although his mother was a blonde and his wife's father was a blonde, that it
is pretty obvious that neither he nor his wife have blonde genes. What do say to
your friend? Use a chart or diagram to support your conclusions.
Answer:
Well… my friend has a right to be worried, but he does not currently have
the knowledge of genes, so he doesn’t know how it works. He’s basically stated
everything he needs to know about the blonde hair gene traveling, he just
hasn’t figured it out yet.
To answer him blatantly, “It is also possible for both parents to be carriers,
in which case their children have one chance in four to inherit the recessive
gene from both parents. When a child looks like neither parent, it’s best to try
and understand genes rather than doubt paternity.” (Berger, 2014, p. 56)
Directly blaming your partner, although possibly justified, should never happen. It
causes stress on your relationship, and can damage the bond you two have.
Although, this is a different lesson for a different day! What I’m trying to get at is
our genes have a lot of play in how we look, and not just our direct genes, our
parents’ genes play a role in how our children will look as well.
To state it in a deeper meaning that gives a complicated answer,
“…alleles interact in a dominant-recessive pattern, in which one allele, the
dominant gene, is far more influential than the other, the recessive gene. When
someone inherits a recessive gene that is not expressed in the phenotype, that
person is said to be a carrier of the gene: the recessive gene is carried on the
genotype.” (Berger, 2014, p. 54)
Let’s simplify that a bit. Even though my friend and his wife do not have
blonde hair, they possess the genes because his wife’s dad had the blonde hair,
so she now possesses the recessive blonde gene. In the same sense, my friend
has the blonde hair gene because his mom has the same gene and it passed to
him, in the same recessive trait.
With them both possessing the blonde hair gene, they now have a
chance to pass the full blonde hair gene onto their children. Even though the
chances are small that they will actually pass the gene on (one in four chance)
it’s not impossible, and it has happened in past times by many other couples.
This chart should show the flow of the gene as well:
Br.
bl.
Br.
Br.
Br.
bl.
Br.
bl.
(For argument’s sake, my friend is the top, and his wife is the side bar,
even though they are both the same, it helps the flow of the layout.)
My friend and his wife both have the blonde and brown hair gene. The
brown hair gene is represented by the capital ‘b’ because it’s dominant; it’s
more likely to show. The blonde hair gene is represented by a lowercase ‘b’
because it’s recessive, and has less likely chances of making an impact on the
child’s physical appearances. When you mix the brown and blond hair gene
together, the hair will still be brown because it’s the dominant gene. Even when
you mix blonde with brown, it’s still brown. The order of mixing doesn’t matter, it’s
what is matched with what that will make the impact. So when the blonde and
blonde genes are mixed, you have the blonde gene show through.
Although my friend had somewhat a right to panic over his child, his fear
was nothing in the end. He simply didn’t understand how the genes he and his
wife possessed, and that these genes can pick for them what their kids will look
like.
Reference List
Berger, K.S. (2014). Invitation to the life span (2nd ed.). New York, NY: Worth
Publishers