Vocalizations in newborn mice: Genetic analysis

Abstract

Two kinds of vocalizations are produced by newborn mice: whistles (between 50 and 150 ms in length), having a narrow bandwidth in each strain that ranges from 30 to 90 kHz; and clicks, which are shorter (about 1 ms) and have a larger bandwidth. These vocalizations were individually recorded in 1-day-old pups from seven inbred strains of laboratory mice, at two temperatures (23 +/- 0.5 and 15 +/- 0.5 degrees C). The numbers of clicks and whistles were counted under these two conditions. Moreover, the length and frequencies at the beginning, apex, and end of the whistles were measured during the 15 degrees C condition. Correlations, including several components-additivity, epistasis (between homozygous loci), and maternal environment-were calculated between the characteristics of the whistles during the 15 degrees C condition. Clicks and whistles were also counted from 1 to 8 days of age during the 15 degrees C condition. The numbers of clicks and whistles were age dependent, with a decrease from day 1 to day 8 for the clicks and a consistent production of whistles. A quantitative genetic analysis was also performed on the 1-day-old pups from the Mendelian generations produced by the inbred strains most contrasting for the number of whistles produced in the cold condition: NZB/BINJ and CBA/H. The heterozygous genotype of the mother induced an increment of the number of whistles. Moreover, a significant part of the additive variance was suspected from the first design, and found with the second one, for this variable. Quantitative genetic analysis showed significant dominance and epistasis between homozygous loci and homozygous and heterozygous loci. This points to multigenic correlates for the number of whistles in this population. The significant additive values for all the variables recorded during the 15 +/- 0.5 degrees C condition and for the number of whistles produced during the 23 +/- 0.5 degrees C condition are compatible with an effect that indicates neither directional nor stabilizing selection. This result is examined in the light of the multichannel sensorial process implicated in maternal behavior in mice.

Effects of Genetic Background, Gender, and Early Environmental Factors on Isolation-Induced Ultrasonic Calling in Mouse Pups: An Embryo-Transfer Study

“…This is in accordance with a bulk of observations of strain differences in the emission of ultrasonic vocalizations in mice (Bell et al 1972;Cohen-Salmon et al 1985;Hahn et al 1987Hahn et al , 1997Hahn et al , 1998Hahn and Schanz 2002;Hennessy et al 1980;Robinson and D'Udine 1982;Roubertoux et al 1996;Sales and Smith 1978;Thornton et al 2005), and adds to other differences between B6JOla and B6N.…”

“…Finally, it can be noted that the virtual absence of gender differences in infant mice calling is in accordance with the vast majority of the literature (Hahn et al 1997, Hahn et al 2000Hahn and Schanz 2002;Roubertoux et al 1996;but see: Hahn et al 1998). …”

“…Also, genetic analyses using reciprocal hybrids (Hahn et al 1987(Hahn et al , 1997(Hahn et al , 1998Hahn and Schanz 2002;Roubertoux et al 1996;Thornton et al 2005) revealed an influence of the genetic background on ultrasonic call emission; a finding, which is supported by studies on knockout mice. For instance, it was shown that several genes are involved in the production of ultrasonic vocalizations, especially Foxp2 (Shu et al 2005).…”

“…Apart from acute and short-term effects, however, there are also data suggesting that maternal behavior can have long-term effects on ultrasonic calling of pups during isolation. Such long-term effects were indicated by genetic analyses, where small but persistent maternal effects on call rate, duration, frequency, and frequency modulation were observed (Roubertoux et al 1996; Thornton et al 2005). A possible mechanism for maternal effects on ultrasonic calling was observed by D' Amato and Populin (1987) who found that call rate of normal mouse pups was reduced when reared by deaf mothers, indicating that the absence of an adequate response by the mothers can result in a reduction of calling behavior.…”

“…Within the species Mus musculus, inbred strain differences in call rate and call characteristics have been consistently observed (Bell et al 1972;Cohen-Salmon et al 1985;Hennessy et al 1980;Robinson and D'Udine 1982), and genetic studies have shown, in summary, that call rate and probably all acoustic call characteristics have a multiple genetic background (Hahn et al 1987(Hahn et al , 1997(Hahn et al , 1998Hahn and Schanz 2002;Roubertoux et al 1996; Thornton et al 2005). Ehret (2005) explained this observation by the fact that genes in three main areas of the infant development may affect ultrasonic vocalizations, namely genes, which contribute to the perceptual pathways of the nervous system that are responsible for the perception of the releasing stimuli, genes that are involved in the regulation of emotion and motivation, and genes that are linked to the anatomical properties of the breathing system and larynx.…”