Learning genetics

Learning genetics

Postby zkramm » Sun Jan 05, 2014 9:14 pm

Hi guys I'm intrested in breeding Leo's. but I would like to understand the genetics behind the different morphs. Everything I read online either blows my brains or confuses me. Is there a simple to read book on genetics? Thanks in advanced
Zane
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Re: Learning genetics

Postby Chamssss » Mon Jan 06, 2014 5:04 am

When it comes to these things you learn a lot from what you start with.

Its always good to start with some fairly simple morphs and from that - and with reference to information you can find on the net- you can begin to understand the basics about their genetics.

Desired traits can be produced by understanding the genetic background of the individuals, and in some cases, selective breeding takes a part of the process.

With regards to genetics, become familiar with terms such as: homozygous, heterozygous, complete dominance, codominance, recessive phenotypic characteristics and genotypic characteristics.

Quite a number of highly desired traits are brought about recessive characteristics (such as albinism) to put it simply both parents need to carry the gene (homozygous or heterozygous for that trait) for it to show visually in their offspring (phenotypically).

I suggest you check out what morphs you can get at a reasonable price and try working with them for a bit to get a better understanding of genetics and how they work.
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Re: Learning genetics

Postby Rabid.Evo8691 » Wed Jan 08, 2014 7:11 pm

Firstly do your research!! Leopard geckos are an expensive project to get seriously involved in. Learn from more than one revenue and gather everything you learn and determine what you are going to grasp and what you are not.

With Leopard gecko genetics there are a few rules of thumb to follow.

Learn the recessive mutations (the 7 of them). Learn which recessives are compatible and which should never be bred together.

Learn the polygenetic mutations that are line bred over many generations to get the desired result you are achieving for. ( cannot be passed on as a het)

Learn the co dominant, dominant and incomplete dominant mutation around and what they do genetically to the 1st, 2nd etc generation of offspring.

Go onto youtube, order Ron Trempers latest edition on Leopard geckos. It is the most up to date book on Leos around.

Be careful who you buy from due to many reasons such as bad breeders and the deadly cripto disease.

Just remember breeding Leos won't make you rich. Do it for the love of it and for no other reason.

Regards
Dylan
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Re: Learning genetics

Postby Docmorrie » Fri Jan 10, 2014 1:01 pm

Hallo Zane

Genetics is a wonderful field and it will stimulate you for many days to come. I understand your frustration towards the vast amount of information available on the internet. Please note that there are a lot of wrong information and wrong interpretations posted on the internet as well, so your frustration is understandable.

You may ask yourself where you should start? Well, to be honest, a good knowledge on the basics is vital for a solid foundation. Try to do some basic reading on general genetic principles. The terminology is vital to understand in order to grasp more advanced concepts. Try to focus you reading at first around the following terms and understand the basics of what is it about:

1. The Definition of Genetics
2. What is a gene vs. mutation?
3. Genes vs. Alleles
4. DNA vs. Chromosomes
5. Modes of inheritance
6. Genotype vs. Phenotype
7. Heterozygous vs. Homozygous
8. Recessive vs. Dominant

As soon as you grasp the basic concepts of the above list (list tot exhausted :) ), you will be able to understand the rest much better. Please note, the key is to understand it, and not to parrot it.

As stated in a previous post, there are many forms of mutations / morphs found in leopard geckos, which are grouped into the following inheritance patterns:
1. Recessive
2. Dominant
3. Co-dominant
4. Polygenetic line-breeding

I will suggest that you familiarise yourself first with the above "patterns of inheritance" before you worry about all the different types of gene-mutations / morphs within these groups. It will help you to organise your thoughts around these concepts. When you understand the patterns of inheritance, the rest will merely be attachments on the knowledge that you already know. Start with recessive-inheritance, master it first and then move on towards the next one.

I am busy with a project on basic genetic principles focused on leopard gecko morph breeding. I get frequently asked by newbies "what will I get if I cross this with that..." I am a teacher at heart so I love to empower them with sustainable knowledge. So I thought it through to create a PowerPoint Slide Show with lots of animations to demonstrate everything visually. I received very positive feedback on it. Currently I only completed the "The Recessive Gene", but you are more that welcome to drop me an email, then I will forward the file to you.

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Re: Learning genetics

Postby Rabid.Evo8691 » Mon Jan 13, 2014 8:30 pm

Also Remember that the genetics Gregory Mendez teaches is completely different than that of Leopard gecko genetics. The fundamentals are the same but some polygenetic traits work as recessives such as the red stripe trait and that dominant, incomplete dominant and co dominant traits are very much blurry at this stage. I believe the Enigma and White and yellow to act as incomplete dominant genes.
The Mack , Gem snow and Tremper giant act as co dominant genes and the Wild type, super snows and Tremper super giant act as dominant traits.

The internet isn't the best way to grasp genetics. I was fortunate enough to have someone willing to teach me the crash course which made my life so much easier.
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Re: Learning genetics

Postby Geckotails » Thu Jan 16, 2014 11:12 pm

W&Y is actually a Dominant morph, one of the Most expensive single gene morphs!!!
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Re: Learning genetics

Postby Rabid.Evo8691 » Fri Jan 17, 2014 12:36 am

Do all offspring hatch out 100% white and yellows from a white and yellow x to a non white and yellow pairing ??

That will determine its dominancy.
A super snow or wild type are dominant as they are always expressed in 1st generation offspring.
Genetics is very debatable and interesting especially with Leos and how different it is from Gregory Mendels calculations.
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Re: Learning genetics

Postby Docmorrie » Fri Jan 17, 2014 3:04 pm

Are you are referring to a heterozygous or homozygous White & Yellow (W&Y)? This will determine the expected outcome. Please do not make the mistake to think that a dominant morph must give 100% of that specific morph in the offspring. W&Y is a well documented dominant morph, thus, only one copy of the gene-mutation needs to be present in order to express itself - whether its origin is maternal or paternal is irrelevant.

Dominant morphs typically do not have a super form that differs visually from its single gene counterpart. The "super form" will only be different in the genotype, but not in the phenotype. If there is only one copy of the W&Y gene present it will be a heterozygous W&Y genotype, but with W&Y expression in the phenotype. If there are two copies of the W&Y gene present it will be a homozygous W&Y genotype, but with the same W&Y expression in the phenotype. There is visually (phenotype) no difference between a heterozygous and homozygous dominant morph. The only difference lies in the expected outcome of the offspring. Test breeding is the only way to determine whether it is heterozygous or homozygous. On a different note, many gene-mutations in their homozygous form, recessive or dominant, are documented to be lethal (known as lethal alleles e.g. Cystic fibrosis in humans) which might influence the expected ratios suggested by Mendelian inheritance.

Let me explain dominant gene inheritance with W&Y as an example:

1.) W&Y (Heterogygous) X Normal:
50% W&Y (Heterozygous)
50% Normal

2.) W&Y (Heterozygous) X W&Y (Heterozygous):
25% W&Y - Homozygous
50% W&Y - Heterozygous
25% Normal

*Phenotype will be 75% W&Y Expression and 25% Normal Expression

3.) W&Y (HOMOzygoys) X Normal:
100% W&Y - Heterozygous

4.) W&Y (HOMOzygous) X W&Y (Heterozygous):
50% W&Y - Homozygous
50% W&Y - Heterozygous

*Phenotype will be 100% W&Y Expression


So, the answer to your question on "Do all offspring hatch out 100% white and yellows from a white and yellow x to a non white and yellow pairing ?" will be YES for a homozygous W&Y, but not for a heterozygous W&Y.


Please allow me to correct you on two minor mistakes... Super Snow and Wild Type (Normal) are not dominant. Super Snow is the super form of the co-dominant Mack Snow gene. The wild type is neutral and not necessarily dominant. Examples of mutations that are dominant over the wild type are W&Y and Enigma.
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Re: Learning genetics

Postby Geckotails » Sat Jan 18, 2014 11:10 am

You can't take a co-Dom X co-Dom morph and create a Dominant Morph. SUPER SNOW is a Super Form from Mack Snow, it's the only snow that has a Super form.
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Re: Learning genetics

Postby Rabid.Evo8691 » Mon Jan 20, 2014 6:55 pm

What about Tremper giant to Tremper super giant Arno???? That is also a "co dominant" gene that produces a Super form. Doesn't the het form of the white and yellow gene act like an incomplete dominant heterozygous gene and if bred with another white and yellow incomplete dominant heterozygous gene it will have the capability to produce an incomplete dominant homozygous gene??

To produce a Super snow 2 copies of the Mack snow alleles have to be present but that doesn't mean 100% of the offspring will be 2 allele copied super forms. Doesn't that make it in complete dominant?

In essence a true co dominant gene is dominant to a normal gene and that is why if a Mack snow is bred to a normal is there only a 1:1 in theory hatch rate of Mack snow to normal type ratio. Thus incomplete dominant gene in my opinion is more true.

A leopard gecko has different dna structures to any other living animal including humans. It would be wrong to compare and because nobody has been employed by a University to strictly study how Leopard gecko genetics works we are all making presumptions.
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Re: Learning genetics

Postby Rabid.Evo8691 » Mon Jan 20, 2014 7:09 pm

and yes Morne. Thank you for correcting me. I got ahead of myself. Normal wild types are only dominant to recessive genes. But that doesn't change the fact that the 3 Mack snow, Tremper giant and white and yellow acting as incomplete dominant + het (note the word dominant) and when produced to each other they produce in complete dominant + homo offspring. Most leopard gecko breeders understand the complexity of genetics and if we all had to know genetics the way a doctor would we would all be comparing ourselves to Leos and wouldn't last a season breeding Leos because a doctors annual gross income compared to a Leopard gecko breeders annual gross income is on the opposite side of the equation (worldwide).
That is why people like me that are not in it for the cash carry on breeding regardless of a varsity degree. (Yes you do get intelligent people that don't study further)
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Re: Learning genetics

Postby Rabid.Evo8691 » Mon Jan 20, 2014 7:27 pm

And by the way I do understand Leopard gecko genetics and what genes do what. I do know how the White and yellow gene works and that it works like the Mack snow and Tremper giant gene. I just believe a lot of breeders are using human and certain animal genetics to freely.

use flower genetics as an example

DOMINANT
A dominant Red flower X any other colour flower ( not dominant) = Only Red flowers.

Co dominant

Red flower X white flower = All pink flowers

Incomplete dominant

Red flower X white flower= 1/2 Red flowers + 1/2 white flowers.

Do you see how freely genetic concerning Leos are to muddy to be precise.
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Re: Learning genetics

Postby Rabid.Evo8691 » Mon Jan 20, 2014 9:05 pm

And note how I use the term "act" as a dominant form or co dominant form and not it is a co dominant or dominant form. They are not true representatives of the definition of dominant and co dominant genes.
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Re: Learning genetics

Postby Westley Price » Sat Jan 25, 2014 7:22 am

I'm no pro with Leo genetics, but with snakes co-dominance and incomplete dominance does not have the same definition as what you supplied.

Co-dominance in snakes means Pastel Ball x Normal Ball = 50% Pastels and 50% Normals, what you have called incomplete dominance.

And incomplete dominance is what you have called co-dominance.
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Re: Learning genetics

Postby Docmorrie » Sat Jan 25, 2014 3:10 pm

I think I explained it very well in my previous post Dylan, please refer back to it. White-and-Yellow is dominant, not co-dominant. Please read my post carefully.
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