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Table 1 Major instructions of interest in Avida and their functions

From: An interplay of resource availability, population size and mutation rate potentiates the evolution of metabolic signaling

Instruction Function
Flow-control: Control the flow during genome execution which is otherwise linear
 if-label (f) Executes the next instruction in the genome sequence if the flow head is at a specified label. In the ancestral copy-loop, this instruction makes sure that the division instruction is executed only when the entire genome has been copied.
Reproduction (Biological): Assist in copying of genome sequence during replication
 h-copy (v) Copies a single instruction from parent genome to offspring genome
 h-divide (x) Separates offspring genome from parent and places the offspring organism in the cell faced by parent
 h-search (z) Finds a specified label in the genome and moves a specified head to this label. In the copy-loop, this instruction ensures the flow head returns to the start of the loop on reaching the end of the genome.
Messaging: Allow organisms to send and receive messages
 send-msg (B) Send a message (containing numbers stored in two of the registers) to the neighbor in the direction the organism currently faces.
 retrieve-msg (C) Retrieves messages into specified registers from the messaging buffer
 bcast1 (D) Sends a message to all the eight nearest neighbors
Rotation: Allow organisms to change the direction they are facing
 rotate-left-one (E) Rotates the organism by a unit in the anticlockwise direction
 rotate-right-one (F) Rotates the organism by a unit in the clockwise direction
  1. Note that this list consists of only nine of the most important instructions out of the 32 instructions in our simulations. For the complete list of instructions and their functions please refer to additional information. Some of the terminology used in this table requires an understanding of the Avida organism life-cycle (underlined) and is presented concisely in the additional information