Long-range comparison between genes and languages based on syntactic distances.
OBJECTIVE
To propose a new approach for comparing genetic and linguistic diversity in populations belonging to distantly related groups.


BACKGROUND
Comparisons of linguistic and genetic differences have proved powerful tools to reconstruct human demographic history. Current models assume on both sides that similarities reflect either descent from common ancestry or the balance between isolation and contact. Most linguistic phylogenies are ultimately based on lexical evidence (roughly, words and morphemes with their sounds and meanings). However, measures of lexical divergence are reliable only for closely related languages, thus large-scale comparisons of genetic and linguistic diversity have appeared problematic so far.


METHODS
Syntax (abstract rules to combine words into sentences) appears more measurable, universally comparable, and stable than the lexicon, and hence certain syntactic similarities might reflect deeper linguistic relationships, such as those between distant language families. In this study, we for the first time compared genetic data to a matrix of syntactic differences among selected populations of three continents.


RESULTS
Comparing two databases of microsatellite (Short Tandem Repeat) markers and Single Nucleotides Polymorphisms (SNPs), with a linguistic matrix based on the values of 62 grammatical parameters, we show that there is indeed a correlation of syntactic and genetic distances. We also identified a few outliers and suggest a possible interpretation of the overall pattern.


CONCLUSIONS
These results strongly support the possibility of better investigating population history by combining genetic data with linguistic information of a new type, provided by a theoretically more sophisticated method to assess the relationships between distantly related languages and language families.
Dipartimento di Biologia ed Evoluzione, Università di Ferrara, Ferrara, Italy.
Vincenza
V
Colonna
Alessio
A
Boattini
Cristina
C
Guardiano
Irene
I
Dall'ara
Davide
D
Pettener
Giuseppe
G
Longobardi
Guido
G
Barbujani
D014644:Genetic Variation; D006801:Humans; D007802:Language; D008037:Linguistics; D018895:Microsatellite Repeats; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide