Genetics, descent and Re: Mark Evans

[bluesqueak]

No: HPFGUIDX 86111

--- In HPforGrownups at yahoogroups.com, "justcarol67" 
<justcarol67 at y...> wrote:
> --- In HPforGrownups at yahoogroups.com, "bluesqueak" <pipdowns at e...> 
wrote:
> > Carol wrote:
> > > Clearly Lily's
> > > muggle father (and I think Mark Evans's muggle father as well) 
> > > had some recent squib ancestors who in turn must have had 
> > > witch/wizardancestors. 
> > <Snip>
> > > Lily's mother seems to have been an ordinary muggle. 
> > 
> > 
> > Pip!Squeak:
> > 
> > Not clear to me.
> > 
> > Firstly, there is no evidence apart from a coincidence of 
> > surnames that Mark Evans is related to Harry Potter. My local 
> > phonebook has an entire large page of Evans's. It's a very 
> > common surname.

> Carol:
> We've already covered this topic and I've presented my reasons for
> thinking that the name Evans, Mark's age (the right age to go to
> Hogwarts next year), and his being in the same neighborhood as 
> Harry all point to his being important in the next book--another 
> muggle-born wizard who happens to be related to Harry and may even 
> share his green eyes. I don't want to recycle old arguments but I 
> can provide links if you want them.

Pip!Squeak:
Thank you, I've read them. As for 'we've covered this topic' -
if you can repeat your arguments, I can repeat mine [grin].  

Your theory is that Mark Evans is a distant cousin of Harry Potter. 
There is *no*, NO canon evidence that Mark Evans is in any way 
related to Harry Potter.  

Evan, for those who don't know, is the Welsh language form of John. 
The spelling 'Evan' dates from about the 15th Century - 'Ifan' is an 
alternate spelling.

To say that because two people have the surname 'Evans' they are 
related is roughly as provable as arguing that two people 
called 'Johnson' are related. They might be. But they might well 
have no ancestry in common *at all* - the surname is derived from 
the ancestor's given name. The 'Evan' who gave his name to Mark's 
family line could well be a completely different person from 
the 'Evan' who gave his name to Lily's family line.



> 
> Pip Squeak:
> > Secondly, if magic is due to a recessive gene (rather than a 
> > dominant gene), *both* of Lily's parents must have carried the 
> > gene.  
> > 
> 
> Carol:
> Exactly. If you read my post again, you'll see that I rejected this
> theory and concluded that wizard genetics may work differently from
> genetics in the RW. 

Pip!Squeak:

No, you produced a circular argument.

Carol:
>Maybe, like the gene for red hair, the gene for magical
>powers is recessive and both parents have to have it for it to be
>passed on to the child. I don't think that's the case, though, since
>Lily's mother seems to have been an ordinary muggle. It's JKR's
>universe, I realize, so RW genetics may not apply.

Pip!Squeak:
I.E. you said - magic gene may be recessive. According to this 
theory, Lily's mother is a muggle, her father a squib-descendent. 
Therefore, magic genes can't be recessive. [Are you arguing that 
only squibs-and-their-descendents carry a magic gene?]

Circular argument - you disprove the theory that magic is a 
recessive gene by stating that for your theory to work magic *can't* 
be a recessive gene.

Again, there is no canon evidence that Grandfather Evans was a 
squib, or a descendent of squibs. There is evidence that they were 
proud of having a witch in the family - but opposed to that are many 
statements (Harry, Hagrid) that Lily's family are muggles. 

You don't have to be a squib to be proud of having a witch in the 
family. Lily had a special talent, which won her a place at an 
exclusive boarding school. Her parents were proud that she 
was 'special'. They'd probably have been equally proud if she'd 
turned out to be a musical genius.

There's also the artistic argument. Make Harry's mother a descendent 
of wizards, you ruin the irony that Voldemort was defeated by a 
common muggle born. You also ruin the symmetry of Tom Riddle [Half-
blood] and Harry Potter [Half-blood]. And the Trio's symmetry (pure, 
half and muggle blood).


Personally, I don't think JKR is that sharp on actual genetics, (the 
poor woman has a French/Classics degree, not biology) but I think 
that her imagined magic inheritance is probably a recessive. She 
seems to think along those lines in her interview explanations.

I agree that it may have some magical component, for example that 
witches and wizards are generally *only* attracted to muggles who 
carry one copy of the recessive gene. But 'recessive' broadly agrees 
with canon - squibs *must* be incredibly rare if every witch/wizard 
has two magic genes [they'd be the result of a bad copy of the 
gene]. 

Marrying a muggle born wizard/witch would still produce magic 
children (muggleborns have two magic genes just like pure bloods). 

Those who marry muggles with one magic gene(rather than muggle 
borns) have a fifty-fifty chance of producing magic children.

Those who marry muggles with no magic gene would have no magic 
children - but we may be talking about the Uncle Vernons of the 
muggle world. No witch/wizard would dream of getting married to an 
Uncle Vernon.

Further, a recessive mutation would mean that there would be 
genuine, no magical ancestors *at all* muggle borns out there. The 
original magic gene would have been a single genetic mutation in a 
single person. At some point, two of his/her descendents produced a 
child with two copies of the gene. And we have the first 
witch/wizard [shaman?].

But by the time that child with two copies was born, there were 
probably quite a few people out there with single copies. They are 
not magical, they have no magical ancestors, and they produce no 
magical children.

Until a future descendent meets and has kids with someone who also 
has a single copy...



Pip!Squeak