rofpm:

Mrs. Rowling,

I read your statement that the wizarding gene is dominant.  I have heard criticism that this does not explain muggle-borns, squibs, or the steady inheritance pattern of magical abilities; but I got your back.  Magical ability could be explained by a single autosomal dominant gene if it is caused by an expansion of trinucleotide repeats with non-Mendelian ratios of inheritance.

As we all know, DNA is made up of the nucleotide bases guanine, cytosine, adenine, and thymine.  The sequences of these bases determine what products are transcribed.  Trinucleotide repeats are one such possible sequence. Huntington’s disease is a well-known genetic condition.  The Huntington’s Disease Collaborative Research Group (1993) proved that the disease was caused by CAG (cytosine-adenine-guanine) trinucleotide repeats.  The Huntington gene is dominant and autosomal (not linked to sex chromosomes).   Normally, a person has 11 to 34 CAG repeats in the gene of interest, which causes the transcription of the normal huntingtin protein.  Unfortunately, when an individual has 42 to over 66 CAG repeats, the abnormal huntingtin protein transcribed causes serious symptoms later in life.  The huntingtin gene with an abnormal number of repeats shows dominant patterns of inheritance over the huntingtin gene containing a normal number of repeats.  Let us postulate that the gene determining magical ability contains trinucleotide repeats.

Read More

I’m adding the end and PS of the letter cause I don’t understand most of the biology things but I thought that bit was pretty cute :)

Sorry this is late.  I was not a biology major when I started reading Harry Potter in third grade.  I think your Harry Potter encyclopedia should include a section better explaining the genetics of magical abilities.  These are my hypotheses about wizarding genetics, and if you do not like them there are probably plenty other ideas out there.  All of your original fans are grown up now and I am sure the ones who became geneticists would gladly give you their input.

Much love,Andrea Klenotiz

PS.  Please sign the enclosed picture so I can frame it and tell everyone the story of how I sent JK Rowling a six page scientific paper about wizarding genetics.

‘I was not a biology major […] in third grade.’

‘All of your original fans are grown up now’, I wonder if JK Rowling realises how big of a part she played in raising these kids.

(via thenotionclub)