Genetic Recombination Sex-linkage

[TomDeGraaff]

Having mentioned it in another thread, I wondered if this has occurred with any finches or other birds.

I know personally of the lutino-pearl, cinnamon-pearl in cockatiels.

I suppose, the recombination event is most obviously (but not exclusively) seen when two sex-linked mutations end up together (I'm trying not to get too technical here but that may change!!!)

So, my first thought is: what sex-linked mutations are there around in finches?

Fawn Zebra and ...... ???? Help me out please. While I have the technical knowledge, I have very little experience or knowledge of the more recent stuff!!!!

[maz]

hahaha this could be an interesting thread ( I had an interesting conversation about the possibilities with lacewing budgies the other day after I bought it up on that thread, someone thought that when mating a lacewing to an ino you wouldn't get inos....and then I got asked about the next generation?????)

[Craig52]

G'day Tom,you are confusing yourself by saying fawn is sex linked,its not,it's autosomsal recessive.Cinnamon is sex linked,eg cinnamon diamonds,cinnamon doublebars. It becomes very confusing as these two mutations and others are called fawns,stars are another that have both cinnamon and fawn mutations and are very simmilar to look at. Craig

[TomDeGraaff]

Thanks Craig. See how much help I need

[finchbreeder]

Unfortunately. Officially them sex linked Zebs are called fawn. Cause they look fawn, even if genetically they are cinnamon. So it is not Tom;s fault it is whoever originally named thems fault.
LML

[natamambo]

G'day Tom,you are confusing yourself by saying fawn is sex linked,its not,it's autosomsal recessive.Cinnamon is sex linked,eg cinnamon diamonds,cinnamon doublebars. It becomes very confusing as these two mutations and others are called fawns,stars are another that have both cinnamon and fawn mutations and are very simmilar to look at. Craig

Except that, as per our other conversation regarding naming conventions, it still depends on who names it. Fawn longtails (so called by the original NSW breeder) are sex linked..... but hey that's another topic .


For those who do not understand what the original post is about... Cells are created in two ways:
* They divide in half, each with a full complement of genetic material, called mitosis. In mitosis the chromosome pairs line up and split in half, each 'half" becomes a new chromosome in the new cell. These are the body cells - bones, tissue, and so on - but not the sex cells (eggs and sperm).
* They divide in half, each with a half complement of genetic material, called meiosis. In meiosis the chromosome pairs line up and then the cell splits in half, each cell getting a whole chromosome but half the number, these are the "gametes" or sex cells, Put two together (one from mum, one from dad) and you have a new cell with a full complement of genetic material which divides into two, four, eight, 16, untl the new baby is fully formed. During the pairing process prior to cell division the sex chromosomes (W and Z in the case of birds) line up together, one new cell getting just one of W or Z, combining these again at fertilisation is what determines the gender of the bird.
* Sometimes when a pair lines the two chromosomes overlap, break at that overlap and re-join, we now have two chromosomes with genetic material from each. Obviously this can't happen with W and Z but can happen with two Ws. Equally, it can happen with all the other chromosomes but the results are more traceable with inherited characteristics if the controlling gene is on the sex chromosome. This overlapping, breaking and re-joining is called "crossing over" or "recombination", hence the original question in this thread.

Now, as it happens lacewing and ino in budgies appeared spontaneously many years apart and in different blood lines. As each is recessive, until (at random) this crossing over appears and puts the genes on the same chromosome at meiosis the two characteristics could not appear together as the birds will always inherit one W from mum and / or one W from dad, each containing either a lace or an ino gene. (Now maz, I've simplified this bit, settle petal ).

Now, back to our main channel.... can't add any more to the list Ure but I'm sure others can!

[Craig52]

Unfortunately. Officially them sex linked Zebs are called fawn. Cause they look fawn, even if genetically they are cinnamon. So it is not Tom;s fault it is whoever originally named thems fault.
LML

I totally agree FB,but i think the KISS formula applies on this forum as the majority really don't want to know about full depth genetics like Natamambo's post
IMO,sorry Graham.
I have no degree in genetics,but i have learnt the whats what over the many years that i have kept mutations and taken the advice from the previous breeders that i have purchased birds from. Craig

[Danny]

Unfortunately. Officially them sex linked Zebs are called fawn. Cause they look fawn, even if genetically they are cinnamon. So it is not Tom;s fault it is whoever originally named thems fault.
LML

The name is firmly stuck in the show standards so nobody would consider changing it now, however right or wrong it is. This is one of those cases where you have to use the wrong name.

[finchbreeder]

I agree totally. Would go if some sod insisted on changing to the correct naming after i have been using the accepted naming for 20/30 years. Love genetics and Natamambos informative posts. Even though he and my daughter (yes she is a double Biology major who starts Honours in statistical genetics in February ) use too many scientific words that get me glazing over at times. I do get most of what they say but.
LML

[Red]

Now, as it happens lacewing and ino in budgies appeared spontaneously many years apart and in different blood lines. As each is recessive, until (at random) this crossing over appears and puts the genes on the same chromosome at meiosis the two characteristics could not appear together as the birds will always inherit one W from mum and / or one W from dad, each containing either a lace or an ino gene.

I thought lacewing was just a composite of ino and cinnamon that occurs during the meiotic crossover events you described? All three colours are sex linked.