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.
Other studies comparing genetic or morphometric dis-tances with linguistic and geographic distances (37, 40-47) rangein scale from a very small 9km (42) to the continental (7000 km for sub-Saharan Africa; refs.45and 46). They vary in numberof samples studied as well, from as few as 4 (47) to as many as 183 (44).722-1726, March1988Population Biology Genetic, geographic, and linguistic distances in Europe (humanvariation/gene frequencies/cranial variables/language families) ROBERTR. SOKAL DepartmentofEcology and Evolution, State University ofNewYorkat Stony Brook, Stony Brook, NY11794-5245 ContributedbyRobertR.