The effects of methyl-donor deficiency on mutation induction and transgenerational instability in mice

Abstract

The effects of methyl-donor deficiency on genome stability.

The effects of extremely low frequency magnetic fields on mutation induction in mice

“…As mutation analysis was performed in BALB/c x CBA/Ca F 1 hybrid male mice, mutations were scored at both the smaller BALB/c-derived allele (~ 2.5 kb) and the larger (~3.3 kb) CBA/Ca allele. Similar to previous studies of mutation detection at ESTR loci Glen et al, 2008;Abouzeid Ali et al, 2012;Mughal et al, 2012;Voutounou et al, 2012), only novel DNA fragments demonstrating a shift of at least 1 mm comparative to the progenitor allele were scored as de novo ESTR mutants ( Figure 13). Given that the Ms6-hm locus consists of a pentamer repeat sequence (GGGCA) n (Kelly et al, 1989), a 1 mm shift in distance equates to either a gain (insertion) or loss (deletion) of three repeat units for the CBA/Ca allele and two repeat units for the smaller BALB/c allele.…”

“…In contrast, several studies have reported that maternal in utero exposure fails to illicit any effect on transgenerational instability (Barber et al, 2009;Abouzeid Ali et al, 2012). Likewise, the frequency of ESTR mutation of unexposed first generation offspring remained similar to control levels following the administration of a parental methyl-donor deficient diet (Voutounou et al, 2012).…”

“…As in previous studies Glen et al, 2008;Abouzeid Ali et al, 2012;Mughal et al, 2012;Voutounou et al, 2012), de novo ESTR mutants were to be identified as novel DNA fragments demonstrating a shift of at least 1 mm relative to the progenitor allele. Inbred strains present Ms6-hm heterozygosity owing to the presence of two very similar-sized progenitor alleles which is problematic when identifying mutants presenting such minimal shifts in distance.…”

“…In contrast, the use of BALB/c x CBA/Ca F 1 hybrid male mice within the current study substantially facilitated the process of ESTR mutation scoring. Such mice possess two differently-sized Ms6-hm alleles, which have been consistently and readily amplified across previous experiments Glen et al, 2008;Voutounou et al, 2012). As such, F 1 hybrid male mice provided a well-spaced banding pattern, through which length-change mutations were easily scored at both the BALB/c-(~ 2.5 kb) and CBA/Ca-derived alleles (~3.3 kb), in addition to the unambiguous establishment of the mutant bands allelic origin.…”

“…Thus, to prevent mosaicism compromising the scoring of mutations in this study, blood and sperm samples of five BALB/c x CBA/Ca F 1 hybrid male mice were analysed for each ELF-field flux density (10 µT, 100 µT or 300 µT) for 2 or 15 hours, in addition to those from the control groups (Table 14). While, as in previous studies (Dubrova et al, 1998a(Dubrova et al, , 2000aVoutounou et al, 2012), all cases of mosaicism within de novo mutations detected in multiple DNA samples, were collectively recorded and scored as a single independent mutation event. Moreover, the presence of a third non-parental allele within somatic samples was disregarded and not included in the mutation analysis.…”