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Guide to genetics (This article is still under construction)

by Thomas Grochalski

Preface

In the table of contents I will write the status of the sections - i.e. how much of the text I have translated from the original Danish into English.
Note: Three figures (figure 2, 3, and 17) contains text which have been written i Danish, due to the fact I wrote this guide almost a year ago in Danish (which is my first language, English being my second). For the most part these figures are self explanatory, but until I get the time to reconstruct these figures with English text, I have translated the text in the figure captions. I hope this solution is acceptable until they are properly translated - however translating the main text have first priority.
This guide will explain how genetics and genetic inheritance works. After reading this guide you will have a good understanding on genetics terms, understanding the principles behind genetics, understand the different modes of inheritance - and because of all this you will be able to predict outcome from genetic crosses - and most crucially be able to understand sudden surprises in the outcome from genetics crosses.

This guide have been divided into three different sections, indentified by the colour in the table of contents, as well as the headlines. The black sections are, I believe, essentiel for understanding genetics, and to be able to use it in real life situations. The orange section can be essential - but only if you breed pied-sided or plan to breed pied-sided. The red sections are non-essential, but they provide a further understanding of the genetics and as such it is nice to understand these sections as well. However, you will be able to predict outcome from your corn snake breedings without reading these sections.

Introduction to genetics In process
Haplosufficiency In process
Why are the two anery morphs not compatible? What about the different hypo morphs? In process
Inheritance
Gensymbols with corn snakes
Typical phenotypic ratios
Modification genes
Sex linked inheritance
Linked inheritance
Selective breeding
Morphs in the nature
Where do we get the morphs?
Ending

Introduction to genetics

This section is under construction...

Homozygous = Two identic alleles of a given gene
Heterozygous = Two different alleles of a given gene

Genotype: AA, Phenotype: A, (homozygous)
Genotype: Aa, Phenotype: A, (heterozygous)
Genotype: aa, Phenotype: a, (homozygous)

Genotype: A⁺A⁺, Phenotype: A⁺, (homozygous)
Genotype: A⁺A¹, Phenotype: A⁺A¹, (heterozygous)
Genotype: A¹A¹, Phenotype: A¹, (homozygous)

Figure 1: Incomplete dominans or co-dominans. A: Incomplete dominans, B: Co-dominans.

Haplosufficiency

This section is under construction...

Figure 2: Haplosufficiens eller haploinsufficiens, forskellen mellem om en allel agerer recessivt, dominant, inkomplet dominant eller co-dominant overfor vildtypen.
Note: the text in this figure is written in Danish, which explains the small differences in spelling. The English text is almost the same compared to the Danish, but below are the translations just in case (written as DK:UK):
Homozygot: Homozygous
Heterozygot: Heterozygous
Normal funktion: Normal function
Gen produkt: Gene product
The most important definitions should have been covered now, and I will now turn to more specific examples.

Why are the two anery morphs not compatible? What about the different hypo morphs?

This section is under construction...

Anery A: Denne type bliver typisk blot omtalt som "anery", hvilket jeg også vil gøre
Anery B: Denne type bliver typisk blot omtalt som "charcoal", hvilket jeg også vil gøre

Hypo (A)
Strawberry (A)
Christmas (A)
Sunkissed (B)
Lava (C)
[Amel (D)]
Ultra (D)^{(note 1)}
Dilute (E)

Hypo locus: H⁺: vildtype, h^h: hypo, h^s: strawberry, h^c: christmas
Sunkissed locus: S⁺: vildtype, s^s: sunkissed
Lava locus: V⁺: vildtype, v^v: lava
Amel locus: A⁺ vildtype:, a^a: amel, a^u: ultra^{(note 1)}
Dilute locus: Dt⁺: vildtype, dt^d: dilute

Note 1:.

Inheritance

This section is under construction...

Figur 3: Opbygning af et Punnett square med et enkelt gen.

Figur 4: To muligheder for at opbygge et Punnett square med to forskellige gener.

Figur 5: Et Punnett square som viser hvor lille sandsynlighed der er for det ønskede resultat ved tre gener.

Figur 6: Et Punnett square som viser hvor lille sandsynlighed der er for det ønskede resultat (aabbttgg) ved fire gener. Dog kan man også se at der vil komme mange forskellige individer ud, hvilket samtidig kan gøre det til et interessant projekt.

Figur 7: Eksempler på Punnett squares over muligheder af afkom ved et enkelt dominant gen.

Figur 8: Et Punnett square som viser hvordan man regner med dominerende alleler sammen med recessive alleler.

Figur 9: Eksempler på Punnett squares ved et gen med mere end to forskellige allele former.

Figur 10: Eksempler på Punnett squares ved et gen med mere end to forskellige allele former.

Gensymbols with corn snakes

I denne liste nævner jeg brugte gensymboler ved kornsnoge. Alle disse er kopieret fra bogen Cornsnake Morph Guide - 2011 versionen skrevet af Charles Pritzel. Der er ikke blevet udgivet en bog i 2012, så de nyeste avlsresultater vedrørende palmetto, pied-sided og tessera har derfor ikke været i betragtning til denne liste.

Albino locus

Allele	Name
A⁺	Vildtype
a^a	Amel
a^u	Ultra

Anery locus

Allele	Name
An⁺	Vildtype
an^a	Anery

Buf locus

Allele	Name
b⁺	Vildtype
B^B	Buf

Caramel locus

Allele	Name
Ca⁺	Vildtype
ca^c	Caramel

Charcoal locus

Allele	Name
Ch⁺	Vildtype
ch^c	Charcoal

Cinder locus

Allele	Name
Ci⁺	Vildtype
ci^c	Cinder

Diffusion locus

Allele	Name
D⁺	Vildtype
D^D	Diffusion

Dilute locus

Allele	Name
Dt⁺	Vildtype
dt^d	Dilute

Hypo locus

Allele	Name
H⁺	Vildtype
h^c	Christmas
h^h	Hypo
h^s	Strawberry

Kastanie locus

Allele	Name
K⁺	Vildtype
k^k	Kastanie

Lava locus

Allele	Name
V⁺	Vildtype
v^v	Lava

Lavender locus

Allele	Name
L⁺	Vildtype
l^l	Lavender

Masque locus

Allele	Name
Mq⁺	Vildtype
Mq^M	Masque

Motley locus

Allele	Name
M⁺	Vildtype
m^m	Motley
m^s	Stripe

Palmetto locus
Endnu intet gensymbol. ^{(note 4)}

Pied-sided locus
Endnu intet gensymbol. ^{(note 5)}

Sunkissed locus

Allele	Name
S⁺	Vildtype
s^s	Sunkissed

Terrazzo locus

Allele	Name
Tz⁺	Vildtype
tz^z	Terrazzo

Tessera locus
Endnu intet gensymbol. ^{(note 6)}

Note 4: På tidspunktet denne liste blev beskrevet havde man endnu ikke reproduceret denne morf. I 2011 blev den bevist til at være arvelig, og mutantallelen til at være recessiv til vildtypen.

Note 5: På nuværende tidspunkt er genetikken ved Pied-sided genet ikke forstået fuldstændigt. Man ved der er tale om et gen hvor mutanten er recessiv til vildtypen. Det man endnu ikke har kortlagt er om det er en ny allel af diffusion-genet eller om det er en nyt gen, som kun kommer fænotypisk til udtryk sammen med Diffusion. Yderligere avlsresultater forsøger at kortlægge dette.

Note 6: På tidspunktet denne liste blev beskrevet vidste man ikke om mutantallelen var dominerende, eller inkomplet/co-dominerende til vildtypen. Denne er dog efterfølgende blevet vist til at være dominant.

Typical phenotypic ratios

This section is under construction...

Figur 11: Fænotypefordelinger ved 1 gen. a: Her ses tre individer med en fænotype og et individ med en anden fænotype, dvs en 3:1 fordeling. Samme princip er tilfældet ved illustrationerne 7b og 8c-g.

Figur 12: Fænotypefordelinger ved to gener.

Modification genes

This section is under construction...

Figur 13: To Punnet squares som viser forskellen mellem to normale gener og et normalt gen plus et modifikationsgen.

Sex linked inheritance

This section is under construction...

Figur 14: Punnett squares som viser muligheden for et Z-koblet reccesivt gen.

Figur 15: Punnett squares som viser muligheden for et Z-koblet dominant gen.

Guide to genetics (This article is still under construction)

Preface

Table of Contents