Rib Fusions, a New Mutation in the Mouse

Curtailed, a new dominant T-allele in the house mouse

“…The fusions between ribs found in some curtailed heterozygotes links T c also to rib fusions Rf (Mackensen & Stevens, 1960;Theiler & Stevens, 1960). Rf/Rf mice usually die in utero with extensive rib and vertebral fusions; they also lack somites and frequently show exencephaly.…”

Contribution of retinoic acid receptor gamma to retinoid-induced craniofacial and axial defects

“…A number of mouse mutants have been described which exhibit vertebral fusions similar to the latter malformations, including Rf (rib fusions; Mackensen and Stevens, 1960), rh (rachiterata; Theiler et al, 1974), and rv (rib-vertebrae; Theiler and Varnum, 1985), to name a few. The basis for the vertebral defects observed in these developmental mutants is likely mesenchymal, and a similar mechanism may apply to the RARg-dependent RA-induced fusions as this receptor is highly expressed in sclerotome at the time of treatment.…”

The case for somatic crossing over in the mouse

“…The nature of purely somatic patches will usually remain conjectural. An exceptional case has been described by Hoecker (1950) who, in a total of about 2000 mice of the C58 strain (which is aja) found six mosaics with patches of banded and hence presumably agouti hairs; as the male with the Hagedoorn (1912); 2, Dunn (1934); 3, Cloudman & Bunker (1945); 4, Little & Hummel (1947); 5, Bhat (1949);6, Hoecker (1950);7, Morgan (1950);8, Falconer (1951); 9, Morgan (1954); 10, Lyon (1958); 11, Phillips (1960); 12, Mackensen & Stevens (1960). most extensive such areas transmitted A w to three out of twenty-four offspring ( Table 2, ref.…”