Any genetics pro's out there??

[Cheeky-x]

Hey...Need a bit of help...ive figured out what het. and homozygous genes are now.(Hurrah) But what i dont know is how do i know if its a het gene or recessive etc etc....like mack snow is hetrozygous right?? (So ive read!) But how do you know what morph has what gene??? Do you all have MEGA memorys or some a bit of paper with it all written down Any hints on how to crack this one??!
Thanks

[bothrops]

From what you've written I'm not 100% sure you have actually 'cracked it'!

The terms heterozygous and homozygous just explain whether the animal is carrying two different versions of the gene in question (het) or two the same (homozygous).

Whether the gene mutation is dominant, codominant or recessive is down purely to what the hets and the homozygotes look like compared to each other.

in a recessive morph the normal (homozygous for the normal or wild type gene) LOOKS exactlythe same as the heterozygous animal (carrying one wild type copy of the gene and one copy of the mutation). For an animal to express a recessive gene it has to have 2 copies of the mutation (homozygous recessive).

With co-dominant genes the homozygous wildtype (i.e. normal) looks different to the het and the homozygous mutant looks different again. Often in this case the het carries the 'mutation name' (mack snow) and the homozygous version is named a 'super' (i.e. super mack)


In dominant genes the het and the homozygous mutant look the same as each other but different to a wildtype animal.

The only way to tell if an animal with a dominant mutation is het or homozygous is to know the parents or to perform breeding trials. That is also the only way to tell is an animal is het for a recessive morph.


Cheers

Andy

[Cheeky-x]

Right....just when i thought i understood it got more confusing...sort of get what you meen though!! Thanks the the reply even to a stupid post!!

[paulh]

I worked in a university genetics lab for several years, which is closer to being a pro than most people on these forums. Andy has it right.

Homozygous and heterozygous describe a gene pair, whether the two genes are the same or different. Dominant, codominant, and recessive describe the relationship between two genes, generally between a normal gene and a mutant gene.