This code is inspired by an Evolutionary Algorithm as discussed by Ray Kurzweil. The idea is to use simple Mendelian biological inheritance to breed two "organisms" with random genetic data to each other to produce an offspring that has inherited "desired" genetic data from them.

evolution_algorithm.py

import string
import random

model_genes = ['1','2','3','4','a','b','c','d']
strand = len(model_genes)/2

def female_code(size, chars=string.digits):
	return list(''.join(random.choice(chars) for _ in range(size)))

def male_code(size, chars=string.ascii_lowercase):
	return list(''.join(random.choice(chars) for _ in range(size)))

class Lifeform(object):
	def __init__(self, female_, male_):
		self.female_genes = female_
		self.male_genes = male_

	def dna(self):
		return self.female_genes + self.male_genes

	def generation(self,num):
		self.branch = num
		return self.branch

def breed(male, female): 
	gene_length = len(model_genes)
	gene_split = gene_length / 2
	x_model = model_genes[:gene_split]
	y_model = model_genes[gene_split:]

	organism_1 = male
	organism_2 = female

	#male dna extract
	o1_x_dna = organism_1.dna()[:gene_split]
	o1_y_dna = organism_1.dna()[gene_split:]

	#female dna extract
	o2_x_dna = organism_2.dna()[:gene_split]
	o2_y_dna = organism_2.dna()[gene_split:]
	
	def dna_match(model_dna, organism_dna):
		gene_test = set(model_dna) & set(organism_dna)
		return list(gene_test)

	def get_inheritance():
		x_traits = dna_match(x_model, o1_x_dna) + dna_match(x_model, o2_x_dna)
		y_traits = dna_match(y_model, o1_y_dna) + dna_match(y_model, o2_y_dna)
	
		offspring_x_traits = sorted(list(set(x_traits)))
		offspring_y_traits = sorted(list(set(y_traits)))

		print "Father's DNA:",sorted(organism_1.dna())
		print "Mother's DNA:",sorted(organism_2.dna())
		print "Child's inherited traits",offspring_x_traits,offspring_y_traits
		return offspring_x_traits,offspring_y_traits

	def produce_child(xi,yi): #takes arrays of inherited DNA
		x_needed = gene_split-len(xi)
		y_needed = gene_split-len(yi)

		child = Lifeform(female_code(x_needed),male_code(y_needed))
		inherited_genes = sorted(xi+yi)
		child_dna = sorted(inherited_genes + child.dna())


		print "Child's DNA:",child_dna


	x_heredity,y_heredity = get_inheritance()
	return produce_child(x_heredity,y_heredity)

breed(Lifeform(female_code(strand),male_code(strand)),
		Lifeform(female_code(strand),male_code(strand)))

wow. that's a nice piece of code! i'm not familiar with the discussion, it makes more sense to me when i ran it a few times locally and saw the output. congrats!