Genomic analysis of a novel spontaneous albino C57BL/6N mouse strain

Abstract

Summary: We report an albino C57BL/6N mouse strain carrying a spontaneous mutation in the tyrosinase gene (C57BL/6N-TyrcWTSI). Deep whole genome sequencing of founder mice revealed very little divergence from C57BL/6NJ and C57BL/6N (Taconic). This coisogenic strain will be of great utility for the International Mouse Phenotyping Consortium (IMPC), which uses the EUCOMM/KOMP targeted C57BL/6N ES cell resource, and other investigators wishing to work on a defined C57BL/6N background. genesis 51:523–528.

No unexpected CRISPR-Cas9 off-target activity revealed by trio sequencing of gene-edited mice

“…(2) To avoid false positives arising from low-allele-fraction mosaic variants in either parent, we removed variants with any alternate-allele reads present in either parent (“parental noise”). (3) We removed any variant coincident with an allele reported in the C57BL/6NJ strain of the Mouse Genomes Project[ 11 ] or specifically in the C57BL/6N Tyr strain[ 17 ]. (4) To avoid further false positives arising from low-allele-fraction mosaic variants present in the parents, we allowed a maximum contribution of only 2% alternate reads from all other (non-parental) samples (“cross noise”).…”

C57BL/6N Albino/Agouti Mutant Mice as Embryo Donors for Efficient Germline Transmission of C57BL/6 ES Cells

“…However, there are reported limitations on the use of BALB/c as an embryo donor, such as substrain-dependent poor response to superovulation [8] , semifertility [9] and a delayed and unequal embryonic development of suitable blastocyts produced for microinjection [3] , [7] . Other alternative embryo host/B6 ES cell combinations have been investigated, for example C3HxBALB/c [10] , C57BL/6J [11] or tyrosinase-deficient albino C57BL/6 mouse strains isolated as spontaneous mutations in C57BL/6- Tyr c-Brd [12] , B6(Cg)- Tyr c-2J [3] and more recently C57BL/6N- Tyr cWTSI [13] . However, besides limited availability of some of these strains, their major drawbacks are i) the inability to detect germline transmission of the mutated C57BL/6 ES cell genome by simple coat color assessment and ii) the difficulty in recovering a pure inbred C57BL/6 background from germline transmitted mice, since an additional time-consuming breeding step is needed to maintain the mutation on a pure C57BL/6 background without coat color mutations.…”