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.
Physical map: A map of the locations of identifiable landmarks on chromosomes. Physical distance between landmarks is measured in base pairs. The physical map differs from the genetic map, which is based purely on genetic linkage data. In the human genome, the lowest-resolution physical map is the banding patterns of the 24 different chromosomes.