mono, di, and trihybrid crosses?

benkillin

I want to write a script that can complete a monohybrid, dihybrid, and trihybrid cross automatically, for those of you who haven't taken 10th grade biology; these types of crosses are to determine the possible traits to be passed to offspring from the parents' traits.

the concept is simple on paper, for an example problem it would be so:

Red flowers are dominant to white flowers (F) if the parents genotypes are as follows
Ff x FF
What are all the different possibilities for the offspring?

First, make a monohybrid cross, because this is only one trait


     F	   f
     -----------
F	|FF   |  Ff|
F	|FF   |  Ff|
	 _______

a dihybrid cross is the same, but more complex,

Red flowers are dominant to white flowers (F), and green seeds are dominant to yellow seeds (S)
The parents genotypes are
FFSs x ffSs

To make things easier, lets make the gametes:
FS Fs fS fs
FS Fs fS fs

The dihybrid cross would be this:

FS	FS	Fs	Fs

fS |FfSS |FfSS |FfSs |FfSs and so on…
fS
fs
fs

a trihybrid cross follows the same pattern (monohybrid has 4 squares, dihybrid has 16, trihybrid has 64) a trihybrid example would be so:
Red flowers are dominant to white flowers (F), and green seeds are dominant to yellow seeds (S) Round seeds are dominant to wrinkled seeds(R)
FfRRss x FFrrSs
And so on…

benkillin

Oh, I forgot to ask my question that motivated me to creat this thred:

How would I go about doing this?

laserlight

Sorry, I got lost somewhere in the biology 🙂

Is this a case of permutations and combinations?
If so, maybe presenting mathematically would be clearer.

Basically, we'll have to try to create an algorithm, then implement it.
If it's fun enough, maybe I'll try to implement it in C++ too 😃

benkillin

ok, ill try my best to present it mathamatically... or rather, programming terms...

imagine a 2 dimensional array

the genotypes are split so only one letter of each trait is in each index, so if the array was
$hybrid['Rs']['rS'] = "RrsS";

after each combination is made, display it in a table.

I hope that makes things clearer. I dont really know about permutations and combinations, but from the looks of a google search, it seems to be similar, but not exactly the same.