Inbreeding effects among inbred and outbred laboratory colonies of Peromyscus maniculatus

Abstract

RIBBLE, D. O., and MILLAR, J. S. 1992. Inbreeding effects among inbred and outbred laboratory colonies of Peromyscus maniculatus. Can. J . Zool. 70: 820 -824. We examined the effects of sibling matings upon reproductive performance among inbred and outbred laboratory colonies of Peromyscus maniculatus. The inbred colony was founded by 12 females collected from one locality in Alberta and bred for 20 generations, with 35 -45 pairs each generation. The outbred colony consisted of first-generation mice born of wildcaught females from diverse areas in Alberta. Consistent with theoretical expectations, there were no differences in reproductive performance between sibling and control (outbred) pairs within the inbred colony of mice. In contrast, sibling pairs had significantly fewer young per litter than control pairs within the outbred colony. Reproductive performance measures (proportion breeding, days from pairing to first litter, number of litters, and total number of offspring produced) were also significantly lower among sibling pairs from the outbred colony than among sibling pairs from the inbred colony. Lastly, we predicted that reproductive performance of the control pairs from the outbred colony would be less than that of control pairs from the inbred colony, due to outbreeding depression. Contrary to our predictions, average litter survival rates were greatest among the outbred colony control pairs. We suggest that the benefits of inbreeding or outbreeding extend broadly across the inbreeding -outbreeding continuum in natural populations of northern Peromyscus. RIBBLE, D. O., et MILLAR, J. S. 1992. Inbreeding effects among inbred and outbred laboratory colonies of Peromyscus maniculatus. Can. J . Zool. 70 : 820-824. Nous avons examink les effets d'accouplements entre individus de la m$me famille sur la performance reproductrice chez des colonies de laboratoire consanguines et non consanguines de Peromyscus maniculatus. La colonie consanguine a Ct C fondCe par 12 femelles capturCes en une localit6 en Alberta et gardCe durant 20 gCnCrations; chaque gCnCration y Ctait assurCe par 35 -45 couples. La colonie non consanguine Ctait constituke de souris de premikre gCnCration nCes de femelies capturCes en nature en divers points de 1'Alberta. Tel que prCvu selon les hypothkses de dCpart, il n'y avait pas de diffkrences dans la performance reproductrice entre les couples de la meme famille et les couples tCmoins (non apparentks) chez la colonie consanguine. En revanche, au sein de la colonie non consanguine, les couples apparentks produisaient significativement moins de petits par portCe que les couples tCmoins. Les mesures relikes B la performance reproductrice (proportion de souris reproductrices, jours CcoulCs entre l'accouplement et la production de la premikre portCe, nombre de portCes, nombre total de petits produits) Ctaient aussi significativement moins ClevCes chez les couples apparent& de la colonie non consanguine que chez les couples apparent& de la colonie consanguine. Enfin, nous avions prCdit que la ...

HIERARCHICAL ANALYSIS OF INBREEDING DEPRESSION IN PEROMYSCUS POLIONOTUS

“…The impacts of inbreeding on some other components of fitness were less consistent, but each trait showed highly significant inbreeding depression, with respect to either the inbreeding of the litter or the inbreeding of the dam, when pooled across populations. Several recent studies on Peromyscus species have also reported greater inbreeding depression in litter size than in juvenile survival and growth (Brewer et al 1990;Keane 1990;Ribble and Millar 1992). Bowman and Falconer (1960) found inbreeding depression in litter size of laboratory house mice to be even more severe than we observed for Peromyscus.…”

Role of inbreeding depression and purging in captive breeding and restoration programmes

“…Unfortunately, we know little about the genetic basis of inbreeding depression in most natural populations; however, there appears to be a general consensus that deleterious recessives are more important than overdominance (Crnokrak & Barrett 2002;Keller & Waller 2002;Kristensen & Sørensen 2005). In laboratory experiments, populations often exhibit responses to purging that suggest most inbreeding depression is due to highly deleterious recessives (Bryant et al 1990;Ribble & Millar 1991;García et al 1994;Saccheri et al 1996;Swindell & Bouzat 2006a). However, other laboratory studies indicate purging is at best only Complete purging of genetic load, as might be expected with highly deleterious alleles, results in a recovery of fitness after a period of reduced fitness.…”

Survival of Dispersing and Philopatric Yellow-Bellied Marmots: What Is the Cost of Dispersal?

“…For female marmots, philopatry may entail reproductive costs such as inbreeding depression (Johnson and Gaines 1990) and reproductive inhibition (Armitage 1988). Inbreeding depression has not been measured in marmots, but estimates of the loss of fitness due to close inbreeding in some other mammals and birds range as high as 15-42% (Hill 1974, Bengtsson 1978, Shepher 1983, Keane 1990, Ribble and Millar 1992. Reproductive maturity in marmots is reached when 2 yr old, but philopatric female marmots that live near older female relatives often fail to breed until 3 yr old (Armitage 1986).…”