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Abstract

Previous divergent selection for nest-building behavior at 22 +/- 1 degrees C resulted in a 40-fold difference between the high and the low lines in amount of cotton used to build a nest. Correlated responses to selection indicated positive genetic correlations with body weight, nest-building at 4 +/- 1 degrees C, and litter size and negative genetic correlations with food consumption. At generation 46, the replicate high-selected (High 1 x High 2), randomly bred control (Control 1 x Control 2), and low-selected (Low 1 x Low 2) lines were crossed and the F1 showed significant heterosis for nest-building behavior. Regression of the F3 on the F2 generation gave heritability estimates of 0.16 +/- 0.10 for the high and 0.07 +/- 0.10 for the low cross, revealing a potential to break the selection limit (at least in the high direction), which had been reached at about 20 generations of selection. Indeed, renewed selection resulted in responses in both the high and the low directions of nesting, yielding realized heritabilities of 0.29 +/- 0.02 and 0.30 +/- 0.004, respectively. Replicated renewed selection, using the F3 generation as the base population, in the high direction of nesting resulted in correlated increases in nest-building at 4 +/- 1 degrees C, litter size, and food consumption. Body weight did not change. The positive correlation with food consumption is opposite in sign compared to the original selection experiment. This indicates that the evolutionary potential of a population to adapt to a changing environment not only depends on its current genetic variability in one adaptive trait, but may be constrained by genetic correlations changing over the course of selection.

Crawl-out behaviour in response to predation cues in an aquatic gastropod: insights from artificial selection

“…The magnitude of change in crawl out behaviour in response to artificial selection is similar to that seen in response to artificial selection on parasite resistance in another aquatic gastropod, Biomphalaria glabrata (Webster and Woolhouse 1999) and the response to predation pressure in tree hole mosquito larvae, Aedes triseriatus (Juliano and Gravel 2002). This degree of change has been found in several other taxa under selection for other behaviours that may have high fitness consequences such as: migration behaviour in the blackcap Sylvia atricapilla (Berthold and Helbig 1992), resistance to a parasitoid in Drosophila melanogaster larvae (Kraaijeveld et al 2001), death feigning in Cucujiform beetles (Ohno and Miyatake 2007;Miyatake et al 2004), and nest building in mice, Mus domestica (Bult and Lynch 2000). The strong response to selection found in our study suggests that plasticity in crawl out behaviour in L. stagnalis is heritable and therefore has the potential to respond to selection in wild populations.…”

Ovarian Sex Hormones Modulate Compulsive, Affective and Cognitive Functions in A Non-Induced Mouse Model of Obsessive-Compulsive Disorder

“…Our BIG mice showed a larger object recognition memory deficit than the Control mice, both in the sham and OVX groups. However, the SMALL mice also showed a similar memory deficit and, therefore, whether this memory deficit in the BIG mice was due to a genetic correlation between compulsive-like behaviors and object recognition memory, or was due to genetic differences between the two strains caused by founder effects or random drift (Bult and Lynch, 1996, 2000), remains to be elucidated. Also as the BIG and SMALL strains had a RI below 0.5 they appeared to avoid the new object, while the control mice had an index above 0.5 and appeared to favor the new object.…”

“…The mouse model of OCD used for this study was developed from house mouse ( Mus musculus ) strains bidirectionally selected for nest-building behavior (Lynch, 1980; Bult and Lynch, 2000). The stock population for the original selection experiment (Lynch, 1980) was a cross among eight inbred strains, i.e., A, AKR, BLB/c, C3H/2, C57BL, DBA/2, Is/Bi, and RIII, to yield the HS/Ibg outbred strain (McClearn et al, 1970; Lynch, 1980).…”

“…The stock population for the original selection experiment (Lynch, 1980) was a cross among eight inbred strains, i.e., A, AKR, BLB/c, C3H/2, C57BL, DBA/2, Is/Bi, and RIII, to yield the HS/Ibg outbred strain (McClearn et al, 1970; Lynch, 1980). This resulted in two BIG strains (BIG1 and BIG2) that use a forty-fold larger amount of cotton for their nest than the two SMALL strains (SML1 and SML2) and two randomly-bred control strains (C1 and C2) that show intermediate levels of nesting (Lynch, 1980; Bult and Lynch, 2000). The BIG strains engage in excessive and repetitive nest building (considered to be homologous to hoarding in humans; Warneke, 1993) and marble burying behavior which is dose-dependently attenuated by fluoxetine and clomipramine, but not desipramine, treatment, making the BIG mice a novel non-induced model for OCD (Greene-Schloesser et al, 2011).…”

“…The nesting scores were square root transformed to obtain a more normal distribution (Bult and Lynch, 1996, 1997, 2000), while the data are presented as non-transformed nesting scores.…”