Genetic diversity in black howler monkeys (Alouatta pigra) from Belize

Abstract

To assess the level of genetic variation in a threatened black howler monkey (Alouatta pigra) population, we examined 36 allozyme loci and restriction fragment profiles of mitochondrial DNA (mtDNA). Mean heterozygosity at allozyme loci was only 0.021 and 5.6 percent of the loci were polymorphic. Analyses of mtDNA also revealed low genetic diversity compared with other primates. F-statistics revealed no significant genetic heterogeneity among troops within the Bermudian Landing preserve, but did indicate a deficiency of heterozygotes at one of the two loci. We explore several explanations for this result, which is unexpected in a socially structured primate. Low genetic diversity in this population may reflect its history of demographic bottlenecks.

Genetic Variation of Mantled Howler Monkeys (Alouatta palliata) from Costa Rica1

“…CENTRAL AMERICAN HOWLERS (ALOUATTA PALLIATA AND A. PIGRA) EXHIBIT EXTREMELY LOW LEVELS OF GE-NETIC VARIATION for plasma proteins and red cell isozymes (Malmgren & Brush 1978, Froelich & Thorington 1982, James et al 1997. This observation contrasts markedly with the high levels of genetic variation shown by howler species from South America (A. seniculus, A. belzebul, and A. fusca;Lima et al 1990, Pope 1992, Sampaio et al 1996.…”

“…They reported variation for two serum proteins and one red cell enzyme, ADA. James et al (1997) studied 41 black howlers (A. pigra) from Belize and found variation for 2 out of 36 loci, including GPI. Overall, our results agree with findings for other Central American populations of howlers, although we found lower levels of genetic variation than those previously reported; all A. palliata individuals examined by us were monomorphic for total plasma proteins.…”

“…Under these circumstances, we would expect to find little or no variation within populations. This was the case for the populations described by Malmgren and Brush (1978), Froelich and Thorington (1982), and James et al (1997), and for those reviewed by Pope (1996). At the same time, random genetic drift promotes genetic differentiation between popula-FIGURE 1.…”

“…This observation contrasts markedly with the high levels of genetic variation shown by howler species from South America (A. seniculus, A. belzebul, and A. fusca;Lima et al 1990, Pope 1992, Sampaio et al 1996. It has been proposed that the low genetic diversity of Central American howlers is due to the action of random genetic drift (Froelich & Thorington 1982, Pope 1996, James et al 1997. Random genetic drift leads to the loss of genetic diversity within populations (Falconer 1989;Futuyma 1989;Ellstrand & Elam 1993).…”

Genetic Variation of Mantled Howler Monkeys (Alouatta palliata) from Costa Rica1

“…This observation contrasts markedly with the high levels of genetic variation shown by howler species from South America (A. seniculus, A. belzebul, and A. fusca;Lima et al 1990, Pope 1992, Sampaio et al 1996. It has been proposed that the low genetic diversity of Central American howlers is due to the action of random genetic drift (Froelich & Thorington 1982, Pope 1996, James et al 1997. Random genetic drift leads to the loss of genetic diversity within populations (Falconer 1989;Futuyma 1989;Ellstrand & Elam 1993).…”