Thank you for those that have replied! And feel free to keep them coming.
To me it’s of interest from developmental biology. Melanocytes (color
producing cells) migrate among the last, to take their stations in the
developing organism. In most cases they move mostly in “balanced”
(symmetric) waves, though not always. Most leucistics are (likely) a
mutation in some stem cell that gave rise to that wave, or in some cases
every one thereafter if the mutation was early enough. It’s of
nonprofessional fascination to me as a natural experiment: predicting which
waves comes in succession, but also the frequency when they’re off that
kind versus another. As if someone took your “color by numbers” and just
said “don’t color any of the #13s.”
Others that are more splotchy can be of other varieties of somatic (ie not
germline) and even germline mosaicsm: everything from Calico cats, to
merling in dogs, to chimeras (split male-females, or sometimes different
colored eyed etc individuals).
I feel most often I get (mostly) bilaterally “balanced” individuals, with a
few rare exceptions. Thank you to (I’ll leave you anonymous) the beautiful
asymmetric Bald Eagle wing. My guess is those individuals are rarer, as
you’d have to have the mutation at a very very specific point, while the
melanocytes were migrating.
Just another way to ponder the beauty underlying things.
Best,
Stephen
On Fri, Nov 19, 2021 at 11:54 AM Andrew Thomas <andy.t@xxxxxxxxxxx> wrote:
I would not describe any of the leucistic birds I have seen as
symmetrical. Some are more "balanced"; that is, more or less the same
amount of white on each side. But I've never seen one with a symmetrical
pattern. Here are some photos of a DEJU and a Black-capped Chickadee, taken
this morning (11/19) in my back garden.
https://flic.kr/s/aHsmX9aorU
Andrew Thomas
On 11/18/2021 4:31 PM Stephen T Bird <isseki.ryotoku@xxxxxxxxx> wrote:
I’d like to know others experience, if you always see the partial
leucistics with bilateral symmetry or if anyone’s ever encountered a nice
asymmetric one?
Stephen
On Thu, Nov 18, 2021 at 12:19 PM Roger Freeman <freemanbecard@xxxxxxxxx>
wrote:
OBOL seems a bit slow this morning so thought I would send some relatively
poor iPhone photos of a leucistic DEJU visiting my feeders. A bit of
variety to add along with the other expected visitors.
Roger Freeman
Silverton
