Generating Anthropological and Archeological Hypotheses in Okinawa through Agent-Based Simulation
status who had two or three wives . Therefore , together with other references , it is assumed that polygamous marriage has been widely diffused in the Japanese mainland from the Yayoi period up until the early modern period . Additionally , we postulated that sustaining more than one wife — polygamous marriage — requires a surplus of food . Therefore , in our simulation model , if the male agent included both of the following variables : polygamous and a high-yielding food production system , namely agriculture , then the agent was assumed to be married to three female agents . A new agent ( child ) inherited the father agent ’ s marriage institution .
Trait Genes : Trait genes determine trait characteristics . Originally , it was thought that trait characteristics are determined through the involvement of many genes in a complex manner . However , to simplify this for the simulation , it is assumed to be composed of a major pair of alleles : the native-type gene ( N ) and the immigrant-type gene ( M ). When a new agent ( child ) is created ( born ), the agent inherits either of the father agent ’ s and either of the mother agent ’ s alleles , that is , the agent ’ s combination of alleles is NN , MM , or NM . In accordance with these combinations , each agent is classified as one with native or immigrant traits . Specifically , a NN agent comprises traits of the native people , a MM agent comprises immigrant traits , and a NM agent displays mixed traits ( mixed people ) and comprises immigrant traits , because the individuals were determined to be immigrants based on the assumption that a person with even a small amount of immigrant traits is an immigrant .
MtDNA Haplogroup : The mtDNA haplogroup variable for an agent was haplogroup D4 , haplogroup M7a , or other . The mtDNA , which is the cell organelle DNA of mitochondria , is inherited maternally and relatively easy to extract from human bone remains . Therefore , mtDNA analysis is a useful way of investigating the origin of the maternal line of ancient peoples . In the frequency of the mtDNA haplogroup of people of the Gusuku period , the frequency of M7a , considered as native type , was 28.6 %. In contrast , the frequency of D4 , with high frequency in the Japanese mainland , was 35.7 % ( Shinoda , Kakuda , & Doi , 2013 ). In our simulation model , when a new agent ( child ) was created ( born ), the agent inherited the mother agent ’ s mtDNA haplogroup as described ahead .
Pottery Style : The pottery style variable was either the native style or the immigrant style . In our simulation model , for the sake of convenience , we restricted the pottery style to either the native or immigrant styles . The argument made by Tsude ( 1982 ) that women produced pottery during the Yayoi period is supported by an extensive ethnographic literature
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