Learning Genetics

[Lisasgeckonursery]

really helpful link thnx, although don't know if my normals are het for anything so may get some suprises one day

[Velenon]

good links and im sure ill be learnign all about this, but ATM thats making me go cross eyed!

Ill have to get my house mate to explain it to me, although she didnt like genetics very much on her course.

[GRB]

Seems like a good explanation of the basics of mendelian genetics.

I didn't see it mention the possibility of linkage drag however - this is something that breeders will have to keep an eye out for as more animals are inbred.

Basically, it is when a trait such as "pastel colour" is joined by another neutral, positive or negative trait that gets carried over during breeding.

For example, you could breed a particular colour variety but also drag across a gene complex that cannot synthesise a particular protein, or that sensitises the animal to a certain disease. The more animals are inbred, the more they increase in homozygosity - if animals lack variation, it usually tends to increase the build up of negative alleles, so linkage drag of negative alleles could become a real problem.

I think it would be nice to see some reference to more realistic genetics in the hobby - mendelian ratios are one thing, but they don't really cover all the potential damages that inbreeding can cause.

[laura1486]

Ouch, giving this a read hurts! Back to revision i guess, less testing

[cfcbulldog78]

lol yes i think i need to go back to college lol

[rmb87]

Originally Posted by SiUK

I really wanna get the grasp of genetics but its seems so complicated to me I look at the links on this thread and its meant to give a basic understanding of it all in a simple way, and I feel stupid.

I suppose its taking one bit at a time if I try and learn the meanings for all the words on that first link and just as importantly the understand them so im not just rattling off something I dont understand, then that will be a good start.

You may find me asking a few stupid questions over the next few months so please bear with me.

I feel the same! It all seems so complicated, and just when i think ive grasped a bit of it, i find out something else that throws what i thought i had learnt Not that i have any plans to breed, just the genetic side of things fasinate me.

[paulh]

Originally Posted by rmb87

... just when i think ive grasped a bit of it, i find out something else that throws what i thought i had learnt ....

I learned genetics in a university course and working in the university genetics lab. Some of the links in this thread look like the blind trying to lead the blind. With the predictable result that they wind up sinking in the bog.

If you can understand why there are four possible outcomes from flipping two coins (heads, heads; heads, tails; tails, heads; tails, tails), you can understand genetics. This is not a mental exercise; I recommend using a couple of coins.

Pritzel's Genetics for Herpers is good, if you are willing to spend some money. Wilmer Miller's A Survey of Genetics is available for download at Wilmer Jay Miller's web site. There are other texts available on the web, too.

[igmillichip]

There are some pretty duff explanations of genetics on the web on snake and reptile sites.

I think that it is fine to show the actual results of crosses as that is useful information, but the attempts at explanations using Punnett square and simple mendelian genetics to 'help' futures breeders is a little short-sighted.

The fact is that when you make crosses with real animals, it is not just ONE gene that is a focus; and if you are considering two traits then it is more than 2 unlinked traits that are a focus in the real animal.

Personally, I feel that when one moves into the realms of breeding real animals then one has to move away from simplistic and somewhat confusing genetics.

Reading many posts on genetics, here and elsewhere, people say that they are confused.......if they are confused over the real science then that is one thing, but they seem to be confused over conflicting mis-information on some info on some links.

Empirical observations are good (and they are the basis of where genetics started), but let's move this on towards holistic predicatbility taking into account 'hidden' traits and linkages.

ian

[Moonleh]

I wrote a guide explaining the terminology for genetics with a few examples to help explain stuff. Planning on adding a calculator (once I've figured out how...). Anyway, thought I'd post a link here: Basic Snake Genetics - explanations of terminology and snake genetics as it might be of use to people.

[paulh]

Originally Posted by Moonleh

I wrote a guide explaining the terminology for genetics with a few examples to help explain stuff. Planning on adding a calculator (once I've figured out how...). Anyway, thought I'd post a link here: Basic Snake Genetics - explanations of terminology and snake genetics as it might be of use to people.

It's a start.

What was your source for "homozygotic" and "heterozygotic"? I'd like to check it out as I hardly ever see those words. "Homozygous" and "heterozygous" are much more common.

Some (hopefully constructive) suggestions:
1. Needs some editing. Some of the sentences are long and difficult to understand.
2. Traits are what you see. They are the effects of the genes. Traits and genes are not the same thing.
3. In a heterozygous pair of codominant genes, the two genes do not interact. Each does its own thing. The combination of effects produces a trait that is different from the trait when either gene is homozygous.

Hope this helps.