# How many chromosomes do corn snakes have?



## intravenous (Dec 20, 2006)

As above. I did a search on google but can't find it.


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## Ssthisto (Aug 31, 2006)

It's quite possible that nobody's bothered to find out yet.


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## toyah (Aug 24, 2006)

I have been looking for this information for ages ... and I finally found it!

(drumroll please)

According to "A Monograph of the Colubrid Snakes of the Genus Elaphe Fitzinger" by Klaus-Dieter Schulz with contributions by André Entzeroth, the answer is 36.


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## intravenous (Dec 20, 2006)

toyah said:


> I have been looking for this information for ages ... and I finally found it!
> 
> (drumroll please)
> 
> According to "A Monograph of the Colubrid Snakes of the Genus Elaphe Fitzinger" by Klaus-Dieter Schulz with contributions by André Entzeroth, the answer is 36.


Apparently 2/3 of all snake species have 36, strange :razz:. I guess its same to assume thats correct then!


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## intravenous (Dec 20, 2006)

That means there are only 18 different chromosomes, so seeing as there must be almost 18 different corn mutations you'd think at least one pair would be linked.


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## 16-BIT (Apr 17, 2006)

pigment colour is controlled by a small amount of amino acid in a single chromosome not mulitple so its only this chrmosome which is affected by the colour mutations. so no not really


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## intravenous (Dec 20, 2006)

16-BIT said:


> pigment colour is controlled by a small amount of amino acid in a single chromosome not mulitple so its only this chrmosome which is affected by the colour mutations. so no not really


If that was the case then they'd all be linked though.


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## toyah (Aug 24, 2006)

16-BIT said:


> pigment colour is controlled by a small amount of amino acid in a single chromosome not mulitple so its only this chrmosome which is affected by the colour mutations. so no not really


In most species, pigmentation and patternation can be modified by multiple mutations on multiple chromosomes. I do imagine that some loci are on the same chromosomes on corns, but if they're only loosely linked then the ratios of offspring might not be so skewed as for us to notice, except if we were producing huge numbers over multiple generations and keeping really exact notes of the offspring, as well as doing some test mating!


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## 16-BIT (Apr 17, 2006)

all colour mutations are mutations of the same chromosome not multiple chromosomes, if the mutation was of multiple chromsomes alot more then just the colour would change!


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## intravenous (Dec 20, 2006)

16-BIT said:


> all colour mutations are mutations of the same chromosome not multiple chromosomes, if the mutation was of multiple chromsomes alot more then just the colour would change!


Most of the mutations are on different genes though and not all of the genes have to be on the same chromosome. Is their evidence that they are that I'm missing?


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## eeji (Feb 22, 2006)

if all colour mutations are on a single chromosome, does that mean if another chromosome was mutated something else would change, eg (extreme example coming up.....) a square head?

why do i always end up going deeper and deeper into things i show the slightest interest in??!!!! i only started with looking at different morphs after i discovered my first corn was orange because its "amelanistic"!!!!!


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## 16-BIT (Apr 17, 2006)

yes. i was born with a chromosomal abnormality and it resulting in me having only 3 fingers on my right hand, this was a small part of one chromosome that was affected. nothing else was affected as it was only one chromosome with the problem.


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## intravenous (Dec 20, 2006)

I don't think all the corn snake mutations are on the same chromosome, bur thats just opinion until scientific evidence can be provided either way.


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## 16-BIT (Apr 17, 2006)

think about it logically, chromosomes are a plan of how you are made, why would the colour bit of the plan be spread all over the place?


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## toyah (Aug 24, 2006)

eeji said:


> if all colour mutations are on a single chromosome, does that mean if another chromosome was mutated something else would change, eg (extreme example coming up.....) a square head?


Different mutations that control completely different things can all be on the same chromosome, or on different chromosomes. If all corn morphs were on one chromosome then we certainly would know about it by now, as breeding results would never even vaguely resemble what we were expecting.

Your "square head" gene could be on one chromosome alongside amel, and then on another chromosome you could have the anery locus sitting right next to another locus that changes head shape.


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## intravenous (Dec 20, 2006)

16-BIT said:


> think about it logically, chromosomes are a plan of how you are made, why would the colour bit of the plan be spread all over the place?


Because our designs aren't necessarily logical, evolution sometimes happens in a funny order.

Basically one gene codes for one protein. It could take several proteins for one colour pigment to be made and these individual proteins could be coded for anywhere on the corn snakes genome.


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## intravenous (Dec 20, 2006)

toyah said:


> Different mutations that control completely different things can all be on the same chromosome, or on different chromosomes. If all corn morphs were on one chromosome then we certainly would know about it by now, as breeding results would never even vaguely resemble what we were expecting.
> 
> Your "square head" gene could be on one chromosome alongside amel, and then on another chromosome you could have the anery locus sitting right next to another locus that changes head shape.


Exactly :smile:. What background in genetics do you have by the way? You seem to know your stuff.


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## intravenous (Dec 20, 2006)

Quoted from the scientific journal: "_Color Mutations in the Corn Snake (Elaphe guttata guttata): Review and Additional Breeding Data, _H. B Bechtel and E. Bechtel"



> The results of the seven crosses among snakes simultaneously heterozygous for albinism and anerythrism are summarized...The expected ratio of white albinos was 1:16, *assuming independant assortmant*. Among the 107 progeny from the seven crosses, 10 were white albinos, *providing preliminary evidence that the loci of the two color mutants are not linked.*


In the above, albino = amel, anerythrism = anery and white albino = snow.

The study was done to see how the amel and anery genes were connected. The conclusion was that the two genes were not linked, and hence independantly assorted (i.e. they are on different chromosomes).

So amel and anery at least are on different chromosomes.


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## eeji (Feb 22, 2006)

my head hurts again!! i never did any biology at school, and any since so i only know the very basics of genetics (picked up when learning about colour morphs). I'm going to have to get myself several large books i think!


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## intravenous (Dec 20, 2006)

eeji said:


> my head hurts again!! i never did any biology at school, and any since so i only know the very basics of genetics (picked up when learning about colour morphs). I'm going to have to get myself several large books i think!


Well I think you've done pretty well with your morph guide considering that then :smile:.


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## Ssthisto (Aug 31, 2006)

16-BIT said:


> think about it logically, chromosomes are a plan of how you are made, why would the colour bit of the plan be spread all over the place?


Because the chromosome - and indeed the gene - isn't conscious of what it does or where it's located - it's just a switch on and off.

In a house, it might be logical for all the light switches for all the rooms to be in one place - in the main entrance hallway - but that isn't how it actually works in practice. The light switches are scattered all through the rooms - and sometimes there's more than one switch or more than one light in each room (two genes on the same chromosome that affect colour) - or no light switches and no lights in a room (a chromosome that doesn't affect colour).


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## toyah (Aug 24, 2006)

intravenous said:


> Exactly :smile:. What background in genetics do you have by the way? You seem to know your stuff.


I don't have any real background in genetics, it's just something I enjoy studying.

I'm doing a talk on corn morphs and genetics at next month's SEAS, if you want to come along and point out where I'm wrong!


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## intravenous (Dec 20, 2006)

toyah said:


> I don't have any real background in genetics, it's just something I enjoy studying.
> 
> I'm doing a talk on corn morphs and genetics at next month's SEAS, if you want to come along and point out where I'm wrong!


SEAS? What's that ?


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