# Useful website



## alcopops (Nov 1, 2011)

Found this and thought it was useful, it may be to others too :Na_Na_Na_Na:
all from The Learning Center Nothing too advanced that will fry your brain but good enough for the average person.

The Learning Center - Acclimation
Acclimating your new pet properly following shipment can be critical to it's health and well-being. If you are purchasing a reptile, read this!

The Learning Center - Genetics 101
Just as the name suggests, this is a quick course covering basic terminology and basic genetic concepts. Includes how basic recessive traits are passed along.

The Learning Center - Genetics 201
The next step in understanding genetics involves combining multiple traits into a single specimen. Details how this happens and predicting the resulting offspring.

The Learning Center - Genetics 301
Introduces the concept of incomplete dominant genes and their seemingly inexplicable effects on appearance of offspring.

The Learning Center - Genetics 401
Discusses advanced genetic concepts such as alleles and loci. Properly understanding these, can explain seemingly mysterious results. Introduces a 'new' form of genetic notation.


The Learning Center - Genetics 501
Discusses trait-linkage, sex-linkage with a brief discussion of polygenic versus autosomal and the difficulties in achieving perfection when working with these types.

The Learning Center - Genetics 601
Now that you've learned how genetics works, here is how to put that knowledge to use.

The Learning Center - Chromatophores
A brief description of the types of chromatophores present in reptiles and their influence on appearance.

The Learning Center - Mutations
A brief description of the types of mutations present in reptiles and their influence on appearance.

The Learning Center - Cornsnake Variation

The Learning Center - Cornsnake Patterns

The Learning Center - Breeding Cornsnakes

The Learning Center - Breeding Rosy Boas

The Learning Center - Breeding Ball Pythons

The Learning Center - Breeding Kenyan Sand Boas

The Learning Center - Keeping Leopard Geckos

The Learning Center - Leopard Gecko Trade Names

The Learning Center - Hybridization Discussion

The Learning Center - Inbreeding Discussion

The Learning Center - Raising Baby Snakes

The Learning Center - Live (F/K) vs Frozen (F/T)

The Learning Center - Help! My Snake Won't Eat!

The Learning Center - Diseases of Reptiles

The Learning Center - Useful Links

The Learning Center - Care Sheets




feel free to move/delete as appropriate, didn't know where to put this : victory:


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## paulh (Sep 19, 2007)

I used to work in a university genetics lab. 

The second and third paragraphs of the Learning Center's Genetics 101 page are wrong. The definitions are poorly written. I skipped through a couple of other of the genetics pages and gave up. IMO, another web site that is wasting band width.


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## alcopops (Nov 1, 2011)

paulh said:


> I used to work in a university genetics lab.
> 
> The second and third paragraphs of the Learning Center's Genetics 101 page are wrong. The definitions are poorly written. I skipped through a couple of other of the genetics pages and gave up. IMO, another web site that is wasting band width.



care to explain where it's wrong ? Be useful to know what you thinks wrong with it instead of a blanket dismissal.

Not sure that it's written for people working with genetics as their day to day job, I'd have they'd be more advanced than 101. From reading it I thought it was just a good layman's guide to reptile genetics. 

: victory:


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## paulh (Sep 19, 2007)

If taught right and some jargon and shortcuts explained, a great many people can handle this sort of genetics as well as those who do it as a day to day job.

I call the Learning Center genetics pages wasted bandwidth because some is wrong and some is pretty confusing. And the rest is pretty average for a herper genetics web site. Details below.

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Genetics 101, starting at paragraph 2.

The underlying principle of genetics is the simple understanding that any trait that differs from the wild type phenotype is produced by one or more pairs of genes producing a block or diversion in an otherwise normal biosynthetic pathway. Most vertebrates have many thousands of gene pairs. One gene in each gene pair is provided by the mother, and the other gene is provided by the father.
　
Chromosomes are found in cells. A chromosome is an organized structure of protein and a molecule of DNA. A chromosome is usually shown as an X-shaped structure. An X-shaped chromosome is dividing into two chromosomes, and this is the stage when a chromosome is easiest to see. 
　
Most adult vertebrates have pairs of similar chromosomes. Both the corn snake and boa constrictor have 18 pairs of chromosomes, while humans have 23 pairs. Each sperm cell gets one chromosome from each parental chromosome pair. A corn snake sperm contains 18 chromosomes. A human sperm cell contains 23 chromosomes. Each egg cell gets one chromosome from each parental chromosome pair. A corn snake egg cell contains 18 chromosomes. A human egg cell contains 23 chromosomes. When a sperm fertilizes an egg, the chromosome pairs are reestablished. 
　
The famous 'double helix' (Figure 1) represents a portion of a single gene in a single DNA molecule in a single chromosome from the father. The two helices are connected by a series of horizontal bars. Each bar represents a pair of bases. The order of the bases is the DNA code. A second double helix would represent the same portion of the corresponding gene in the DNA molecule in the corresponding chromosome from the mother. Two genes in corresponding locations in a chromosome pair form a gene pair. The genetic codes in the two genes may or may not be the same.

(The above needs polishing. But it does say that the double helix in figure 1 is NOT from only one parent. One double helix comes from the father, and a second double helix is from the mother. The two double helices do not merge into one double helix.)
　
Definitions:
Two slightly different genes (A and a) with the same locus can form three gene pairs -- AA, Aa, and aa. 
*Dominant* - Gene A is dominant to gene a if an individual with gene pair Aa looks like individuals with gene pair AA and not like those with gene pair aa.
*Recessive* - Gene a is recessive to gene A if an individual with gene pair Aa looks like individuals with gene pair AA and not like those with gene pair aa.
　
(Codominant - Gene A is codominant to gene a and gene a is codominant to gene A if an individual with gene pair Aa does not look like individuals with gene pair AA and does not look like those with gene pair aa.)
*　*
*Homozygous* - The two genes in a gene pair are the same.
*　*
*Heterozygous* - The two genes in a gene pair are not the same.
*　*
*Punnett Square* - A simple table used by geneticists to determine the outcome of various combinations of alleles. The letters representing each allele passed on by the parents are placed in the top row and left column (shaded light blue here). The resulting combinations are placed into the appropriate squares (shaded White here) and the results can then be tallied up. Usually, the males' genetic traits are listed in the top row, while the females' are listed in the left column. (add - While the Punnett square is the most common method found in textbooks, it is less efficient than a branching system.)

Sheesh, I'm rewriting the page. From here on I'm just hitting the high spots.
　
Add definitions for genotype, phenotype, wild type, mutant, allele. (All alleles are genes, but not all genes are alleles.)
　
Traits are phenotype, not genotype. + is the internationally recognized character standing for a wild type gene. 
　
The rest could be more clearly explained.
　
Explanation of Punnett squares is average.
　
Genetics 201
　
Repeats the false notion that a DNA molecule's base pairs are gene pairs.
　
Needs either description or picture of amelanistic and anerythristic corn snakes. The rest of the page could be more clearly explained. It's no better (and no worse) than many similar pages.
　
Genetics 301
　
As far as the breeder needs to go, incomplete dominant and codominant are synonyms.
　
Salmon is AKA hypomelanistic in boa constrictors. Salmon is the name on the gene's birth certificate, hypo is a nickname. Sa is the assigned symbol in the Journal of Heredity paper that described the salmon mutant back in 2000. The salmon mutant gene fits the definition of dominant better than the definition of codominant. Tiger in reticulated pythons is a much better example of codominance.
　
Sa/Sa = homozygous salmon, Sa/+ = heterozygous salmon, +/+ = normal.
　
incomplete dominant recessive" is a contradiction in terms. No such thing.
　
"In other species involving co-dominance, there may be no difference in appearance between heterozygous and homozygous individuals, ...." Then the mutant gene is dominant to the wild type gene, not codominant.
　
Genetics 401
　
Poorly written definitions. Explanation of multiple alleles average..
　
Genetics 501
　
Linkage, not trait-linkage. Loci are linked, not traits.
　
Locus (singular), loci (plural)
　
Genetics 601
　
Some typos. The character x means "mated to" Using aa x aa is more readable than aa aa. Stops using Punnett square and uses FOIL method. Using a / or // to separate the two genes in a gene pair makes a genotype made up of three or more loci easier to read.
　
aa x aa --> aa, aa, aa, aa can be (but was not) simplified to aa x aa --> 1/1 aa. 1/1 = 100%.
　
Branching system as good as Punnett square with one locus. The branching system begins to shine with 2 or more loci. Branching system is explained late in the Learning Genetics sticky here in the RFUK genetics forum. It just adds branches for each additional locus instead of drawing repeated chequerboards.
　
Questions section is good.
　
Chromatophores
　
Most looks pretty good, but the explanation for T+ albinism is bad.


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## alcopops (Nov 1, 2011)

Hi, thanks for the reply, would have replied earlier 
but i've been on the edge of civilisation lol 

Not had a chance to compare and contrast between the 2 yet 
But it looks like you've carpet bombed it lol

It's always good to have a critique than just the usual "what a load of sh!)("
So thanks for going above and beyond with your reply 

I'm no expert, never claimed to be. For me all i need to know is
What kind of clutch i'd get if i bred a lemon blast with an enchi royal python 
For example and from reading this i feel i kind of do, but now i'm not so sure i'd still
Pass that exam. All the terminology and exact science isnt really an issue for 
me but i understand why it is for some. 

Hopefully i can still change the thread title lol

Cheers


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