13676
Based on phylogenetic reconstruction and power analysis , the first beta ( A ) substitution , found in all Andean individuals , was acquired when ruddy ducks dispersed from low altitude in North America to high altitude in the tropical Andes , whereas the two additional substitutions occurred more recently , when ruddy ducks dispersed from high altitude in the tropical Andes to low altitude in the southern Andes .
 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