published as p38."/>
Figure 3.3 Current symbols assigned to a variety of unrelated genes originally published as p38. If one searches for the gene symbol p38 the results indicate numerous genes on different chromosomes that at one time were all called p38. The new names not only separate out the different genes but also reflect to a degree what is currently known about the gene function. By following the links you can obtain much more detail on each gene, the number and details on allelic mutations, and links to the original and many subsequent publications on the topic (MGI accessed 22 April 2020).
Table 3.3 Inbred strains of mice.
| AdvantagesGenetic and phenotypic uniformity (smaller numbers needed)Well characterized (pathology and physiology)For most standard inbred strains >200 generationsIdeal controls (both biological and sequencing)Permits clear genetic mappingEnables identification of modifier genes |
| DisadvantagesNot as robust (smaller, lower reproductive performance [fecundity], shorter lifespan)Strain‐specific characteristics (deleterious mutations causing strain specific diseases)Expensive (when difficult to maintain) |
| UsesWidely used in all types of researchModels for human diseaseBackground for mice with spontaneous and induced mutations |
Table 3.4 Inbred strain nomenclature.
| C57BL/6J or C57BL/10J |
| C57BL is the parental strain name (since C57BL/6J is the actual strain name) |
| 6 or 10 indicate the substrain line number (C57BL/10J are prone to serious heart disease not seen in C57BL/6J) [8] |
| J indicates the breeder (The Jackson Laboratory) of these substrains |
| C3H/HeJ or C3H/HeN |
| C3H is the strain generated by Strong from a cross of Bagg albino with DBA |
| He is the substrain from the W.E. Heston laboratory at the National Cancer Institute |
| J indicates the subline received from Heston then bred by The Jackson Laboratory |
| N indicates the substrain bred at the National Institutes of Health |
An inbred strain is designated in capital letters.
A substrain is identified using a forward slash (/) after the strain name followed by a lab code of the strain breeder.
Further substrains derived from the founder add to the end of the lab code of subsequent breeders without another forward slash.
Note that C3H/HeJ has a mutation in the Tlr4 gene making it highly susceptible to gram negative bacterial infection while the C3H/HeN substrain is wildtype for Tlr4.
Figure 3.4 Nomenclature for hybrid stocks.
Table 3.5 Examples of inbred strain abbreviations.
| 129P3/J = 129P3 |
| 129S1/SvImJ = 129S1 |
| A/HeJ = AHe |
| A/J = A |
| AKR/J = AK |
| BALB/cByJ = CByJ |
| BALB/cJ = C |
| C57BL = B |
| C57BL/6J = B6 |
| C57BL/6JEi = B6Ei |
| C57BL/6NJ = B6NJ |
| C57BL/10J = B10 |
| C57BR/cdJ = BR |
| C57L = L |
| CBA/CaJ = CBACa |
| CBA/J = CBA |
| C3H/HeJ = C3 |
| C3HeB/FeJ = C3Fe |
| DBA/1J = D1 |
| DBA/2J = D2 |
| NZB/BINJ = NZB |
| NZW/LacJ = NZW |
| RIIIS/J = R3 |
| SJL/J = SJL or J |
| SWR/J = SW |
Table 3.6 F1 and F2 hybrid mice.
| F1 hybrids | F2 hybrids |
|---|---|
| AdvantagesGenetic and phenotypic uniformityContains a 50 : 50 mix of both parental strainsHybrid vigorAccepts transplants of tissue from mice of either parental strain | AdvantagesHybrid vigorF2 hybrids do not have 50 : 50 mix but do have some mice in the population homozygous for some alleles and are valuable as a population for mutant gene mapping |
| DisadvantageNot self‐perpetuating | DisadvantagesNot self‐perpetuatingGenotype and phenotype NOT uniformParental strains most likely reject tissue transplants |
| UsesRadiation researchBehavioral researchBioassays of nutrients, drugs, pathogens, or hormonesTransplant recipientsBackground for transgenics and some deleterious mutations | UseControl for many targeted (“knockout”) mutations on a mixed B6; 129 |
Sibling breeding F1 hybrid mice for one generation produces an F2 hybrid population (Figure 3.4), and continued inbreeding after that eventually leads to the creation of recombinant inbred strains (see below). The F2 hybrid population also has hybrid vigor, but is distinct from the F1 hybrid population because meiosis has resulted in recombinations between the parental chromosomes such that there may be some homozygosity in a minority of the segregating alleles. This makes an F2 hybrid population a tremendous tool for mapping, especially for mapping recessive mutations. For example, if an interesting phenotype is observed in an inbred strain, such as an abnormal hair coat, hair interior defect (hid) in all AKR/J mice, these animals can be crossed with another inbred strain, such as BALB/cByJ, that has normal hair (Figure 3.5). As hid in this example is an autosomal recessive mutation, the obligate heterozygous F1 progeny of this cross will all have a normal hair coat. When these heterozygous progeny are intercrossed to create F2 hybrids, 25% of these mice are expected to have the abnormal hair phenotype. The genetic interval carrying the mutant sequence derives from AKR/J so by screening the DNA from the mutant and unaffected mice in the population