A study was made of three aspects of the genetic composition of some c
at populations in Catalonia (Northeastern Iberian Peninsula, Spain). T
he allelic frequencies of the nine genes (O, A, T, D, L, S, W, C and I
), which control color, tabby and length of coat, were investigated: 1
) the cat population of Llansa only 8 km from the French frontier on t
he Mediterranean coast and a new sample obtained in the rural district
of Castelldefels were shown to be in Hardy-Weinberg equilibrium for t
he O and S loci. 2) The second question concerned; an analysis of the
genetic relationships between the cat population of Llansa and other p
opulations of Western Europe. Ruiz-Garcia et al. (Mis. Zool. 18: 169-1
96, 1995) looked for genetic similarity between cat populations in Nor
thern Catalonia and France. Populations in central and Southern Catalo
nia had been found to be very distant from the French cat populations,
genetically speaking. However, the cat population analyzed in Norther
n Catalonia did not show any increase in the genetic similarity with t
he French populations, and was found to be similar to the other cat po
pulations in Catalonia, previously analyzed. A new sample of cats from
Llansa, the northernmost of all populations in Catalonia sampled up t
o now, showed no increase in genetic similarity to French populations
compared to other groups from Catalonia, The genic frequencies of the
coat characteristics loci showed that the French and British cat popul
ations were furthest away from the population of Llansa, among those o
f Western Europe. In general, the cat populations we sampled in Catalo
nia showed a greater genetic resemblance to Eastern Mediterranean and
North African populations than to the cat populations found in Western
Europe. 3) The third aspect concerns population change over time. In
1989, the genetic composition of a cat population from Castelldefels w
as analyzed. In 1994 this population was sampled again, and no signifi
cant differences were found in the eight allelic frequencies compared,
which demonstrates great stability over time in the genetic profile o
f this cat population.