Here is Iris Cohen's reply in the botany newsgroup.
Her explanation should be sufficient to satisfy the non-biologist.
Bottom line is that both are in the family Rosaceae.
If by genetic affinity, you mean, can they be crossed to produce hybrids?
The answer is no. They are in separate genera that are not interfertile.
Iris Cohen <iriscohen at aol.com> wrote in message
news:20030222085844.04034.00000064 at mb-ci.aol.com...
> << Are apple and peach genetically related (and how)?
>> As I am not a biologist, I tried to simply google this. People say apple,
> and quince are closely related, >>
>> Apples, peaches, & quince are all members of the rose family, Rosaceae.
> don't really need a table for this. In the spring, go out & look at apple
> peach trees. If there are no peach trees around, look at cherry trees &
> them to apples. Look at some other members of the rose family, like single
> flowered roses, hawthorns, shadbush, flowering quince, whatever grows in
> area. You will soon see the traits they have in common. Next fall, look at
> hips and compare them with apples.
> Apples, quince, and pears are closely related. Some authorities place them
> in the genus Malus. They are known as pome fruits because the fruits all
> the same structure, five small seeds enclosed in a hard fibrous container
> inside an edible fruit. Peaches nowadays are placed in the genus Prunus,
> with cherries, almonds, plums, apricots, & all the other stone fruits.
> have an edible fruit with one hard seed in the middle, except the almond,
> has a thin rudimentary fruit and a hard-coated edible seed. They have many
> traits in common with apples: five petals, five stamens, alternate leaves,
> Central NY, Zone 5a, Sunset Zone 40
> "If we see light at the end of the tunnel, It's the light of the oncoming
> Robert Lowell (1917-1977)
>Claudio Jolowicz <claudio-jolowicz at gmx.net> wrote in message
news:b37su9$q8r$07$1 at news.t-online.com...
> Are apple and peach genetically related (and how)?
>> As I am not a biologist, I tried to simply google this.
> People say apple, peach and quince are closely related,
> they show this result by similarity tables, but no web
> site I found made any statements on the genetical affinity
> of apple and peach.
>> Thanks in advance,
>> PS. Sorry for crossposting, some of these newsgroups seem to be
> ill-frequented. Follow-ups to bionet.plants