19704
Despite the high proportion of heteroplasmic individuals in natural populations , we found no evidence for recombination between mtDNA molecules , suggesting that either recombination is rare or recombinant haplotypes are counter - selected .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None