roadmapping genetics

[jwsporty]

Well I am moving right along with my collection and will be doing some breeding in the spring. However I am having difficulties in finding some sort of roadmap of genetics (for lack of a better term). Now what I mean by this is; If I am planning a project to create offspring with the trait I want, how can I identify and develop the program to assure the desire results.

Let's say for argument sake I have the following:

1.0.0. - where the trait desired is the colouration
0.1.0 - where the trait desired is the pattern

when bred together it would be generally expected that I would end up with

50% het for "colour"
50% het for "pattern"

but you would expect to see 1/2 the litter looking like the male and 1/2 looking like the female. Now if one of the offspring from this clutch is bred back to the original male , so we say the offspring showed the desired colour, and the offspring was a female then she would be bred back to the original male to produce new offspring with a stronger gene for the colour. I guess this would be considered at 66% het for "colour"?

So if the 66% het females were bred back to the original male again then am I on track to say that the offspring from this pairing would be 100% het for "colour" and that, at that time it would be deemed proven for a specific genetic trait. At which you would breed one of the offspring from the 100% het group back to the original male to have a solid trait in their offspring. Hence a proven strain.

Hope all of that made sense

So I guess the big question is

(a.) Am I way off base in my thinking and understanding of how the genetics are mapped for a given trait.

and

(b.) Is there a general guideline to breeding somewhere on the net,in a computer program, in books, or through personal breeding efforts; somewhere that will help me get to the desired trait. And how do you identify both the dominant and recessive traits in the animals?

and

(c.) when breeding different subspecies are their acceptable guidelines for producing genetic crosses. I am not talking about breeding kings and corns together. I am thinking of breeding different kings together. Can this be done to achieve desired affects? Say for example, I wish to take my male Lp. g. splendida and cross with female Lp. g. californiae (albino-striped) to develop an albino patterned splendida. Or say taking a female greybanded and crossing with a thayer's variable to produce a stronger or more desired colour in the off spring?

I regularly hear of people breeding for specific looks in the offspring (eg. bigger bands, darker colours, less tipping, etc..you know what I mean).

I find this element of the hobby fascinating and I am looking forward to producing my first clutch. For the time being I will stick with a proven group of Coastal phase Lp. g. californiae but I do wish to experiment down stream with both colour and pattern variations and your qualified answers as always, are greatly appreciated.


Thank for your time.

Jim

[Jeff_Favelle]

1.0.0. - where the trait desired is the colouration
0.1.0 - where the trait desired is the pattern

when bred together it would be generally expected that I would end up with

50% het for "colour"
50% het for "pattern"

No.

If you bred two animal together that actually expressed the gene (if its simple recessive) then the offspring would be all 100% double heterozygous. Not sure where you get your "50%" from.

[vanderkm]

Nor sure how qualified I am to offer an answer but you raise lots of issues in addition to what Jeff has mentioned above - if both parents express a gene that is inherited as a simple recessive (striped pattern in corns or amelanistic coloration) then the offspring will all be het (100% het) for both striped and amelanistic. This assumes that neither of them is carrying (het for) the opposite gene. You would get a 50% probability that each is het if you bred a normal that is het striped to a normal that is not het - offspring would be have 50% chance of carrying the recessive gene.

It gets complicated depending to some extent on the species you are dealing with - since some patterns and colors are inherited as co-dominant or incomplete dominant in some species.

For general genetics information you can check this corn site out - he covers the basics in the genetics tutorial http://serpwidgets.com/cornsnakes/

As far how to identify what is dominant and recessive, I have found the best approach is to discuss with people who breed that species. Might be worth posting what you have and what you are looking to produce to get input on how people would approach it. Things like striping and crazy patterns in Cal Kings are something I would expect several people on this list have experience with.

In my experience the attitudes toward breeding between subspecies differ as much as those related to hybridizing and many people have very strong opinions - with those who are against it being very strongly against it. My only advice would be to tread cautiously there.

best of luck,

mary v.

[jwsporty]

Thank you Jeff and Mary for your input.

As mentioned I am new the breeding scene and I am looking forward to the experiences.

Jeff: I wouldn't read too much into the statement, as I may have described it incorrectly. Should have put the ? mark in there..

Mary: Thank you for your explanation and the link and I will surely check it out. Regarding hybrids, I am aware of the strong opinions related to maintaining true blood lines, respect the reasons, and I plan on following the same practices. At this stage I will be sticking with Lp. g. californiae (coastals, albino striped, chocolate striped). I figure this should keep me busy for a while.

Thanks again

Jim