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Genetics - Advanced - Double heterozygous genes

This bit of drivel is intendet to create a basic knowledge of herp genetics. In my case I rely on python pattern and color mutation as an example.

Overview:

First we need to apply basic genetics to understand color and pattern mutation. We tend to work with numbers that are theoretical expected ratios, the reality of these numbers works better with larger clutch sizes Smaller clutch sizes often provide dispropertional theoretical results.

The following punett square displays the gene pairing of two animals. The "N N" pair denotes the gene pair of alleles of normal appearing animals with no unusual genes Row 1 is one adult and column 1 is the other adult.

    1.) Denotes breeding two normals

Denotes the resulting offspring

The resulting offspring are divided into groups of 25 % when combined they equal the 100 % of the clutch. All babies resulting are " NN " which translates as a normaly appearing non mutation carrying animal.

A simple recessive mutation - a gene that has proven itself is an inheritable genetic trait. When a visible mutation is bred to a normal appearing non gene carrier the resulting offspring are normal appearing animals that carry the genetics of that mutation. These offspring are known as heterozygous. They carry the genetics of the mutation but visually look normal.

In our case here we shall use the gene of albinism she is a proven simple recessive inheritable gene. Do see the gene of albinism at work we are looking for a pair of " a a " which denote an albino Since albinism is simple recessiv we are looking for the lower case pairing If an upper case " N " occurs it will mask the simple recessive gene.

  2.) Denotes breeding an albino  ( aa ) row to a normal ( NN ) column

Denotes the resulting offspring

The resulting offspring are all heterozygous gene carriers ( N a ) they appear normal but carry the gene for albinism. They are important ans allow breeders the needed " hets" to produce albinism through selective breeding.

  3.) Denores breeding a heterozygous ( Na ) to a normal  NN )

Resulting offspring

50 % of these offspring are normal and 50 % are heterozygous albino gene carriers. The resulting babies all appear normal but one out of every two in theory is an albino gene carrier they are known as 50 % possible het albinos.

  4.) Denotes breeding an heterozygous ( Na ) to heterozygous ( Na )

Resulting offspring

This time we are seeing some results 25 % are normales, 50 % are hets and 25 % are visible albinos. The normal looking animals consist of heterozygous animals and normales. These normal appearing animals are called 66 % possible het albinos since 2/3 of them are actually hets but indistinguishable from normals.

  5.) denotes breeding an albino ( aa ) to a heterozygous ( Na )

Resulting offspring

Now we are seeing 50 % heterozygous animals and 50 % visible albinos without any possible hets. 

  6.) Denotes breeding an albino ( aa ) to an albino ( aa )

Resulting offspring

We are seeing an entire clutch of the simple recessive gene albinism. There are no normal appearing animals.

Summary:

We have now taken a simple example of genetics using a known genetic color mutation. This can be replaced by many other mutations with the same percentages and results.

Double heterozygous genes at play:

Denotes breeding two double het ( Albino – Granit ) together

Resulting offspring

Resulting offspring are in theory out of clutches of 16 animals

1 Normal ( NNNN ) 6.25 % of the clutch

2 Het Albinos ( NNNa ) 12.5 %

2 Het Granit ( NNNg ) 12.5 %

4 Double het Albino – Granit ( NNag ) 25 %

1 Albino ( NNaa ) 6.25 %

1 Granit ( NNgg ) 6.25 %

2 Albino het für Granit ( Naag ) 12.5 %

2 Granit het für Albino ( Ngga ) 12.5 %

1 Albino – Granit ( aagg ) 6.25 %

The Breakdown. We take out all of the visible mutation to calculate the remaining genetic odds in the square. We have seven visibles in theory, that leave 9 normal looking animals that have genetic qualities of interest. We take 100 and divide by the number of animals, this equals 11.1 % each animal represents in the normal appearing portion of the clutch. The babies of most importance are the double hets, these 4 make up 44 % of the clutch. The remaining ratios are 22.2 % possible pure het albino, 22.2 % pure het granit ans 11.1 % normal. This breakdown there is a 44 % chance that any one of the normal appearing animals is a double heterozygous fot albino granit. A 22 % chance that any baby is a pure het albino or het granit. A remaining 11 % chance that the baby is a normal.

We hope this helps many people who are trying to get a usable perception or double heterozygous genetics.