Cooing and babbling are early stages of speech development. As babies get older (often around 9 months), they begin to string sounds together, incorporate the different tones of speech, and say words like mama and dada (without really understanding what those words mean).
The map distance between two genes, measured in centimorgans or map units, equals the percentage recombination frequency between the two genes--the likelihood of offspring with copies of those genes on the same chromosome that come from different parents.ave. dna image by Allyson Ricketts from Fotolia.com. The concept of map distance in a genotype refers to where genes are located on a chromosome but does not refer to physical distance; rather, map distance refers to the tendency for a crossover to occur between genes.
While both maps are a collection of genetic markers and gene loci, genetic maps' distances are based on the genetic linkage information, while physical maps use actual physical distances usually measured in number of base pairs.