Delayed development of reflexes and hyperactive locomotion in the spontaneous mutant "waltzing" of the musk shrew, Suncus murinus

New behavioral mutant rat exhibiting circling behavior (clx) controlled by a sex-linked recessive gene

A male rat showing intermittent circling behavior was discovered among the Jcl:Wistar rats in our laboratories, and among its backcross offspring individuals showing the same behavior were found. The abnormalities in these animals were characterized by intermittent circling behavior (walking and/or running in circles) and head tossing with the neck twisted. No abnormalities were observed in fertility, delivery or pup mortality. The results of mating experiments indicated that the circling behavior phenotype is controlled by a single sex-linked recessive gene, and the mutant was named "circling behavior linked to X-chromosome (gene symbol: clx)." This circling behavior mutant is considered to be different from the previously reported mutants, the behavior in all of which has been found to be autosomally inherited. Sib-mating is continuing to produce an inbred strain with this newly discovered circling behavior mutant gene.

Chromosomal mapping of 18S-28S rRNA genes and 10 cDNA clones of human chromosome 1 in the musk shrew (Suncus murinus)

The direct R-banding fluorescence in situ hybridization (FISH) method was used to map 18S-28S ribosomal RNA genes and 10 human cDNA clones on the chromosomes of the musk shrew (Suncus murinus). The chromosomal locations of 18S-28S ribosomal RNA genes were examined in the five laboratory lines and wild animals captured in the Philippines and Vietnam, and the genes were found on chromosomes 5, 6, 9, and 13 with geographic variation. The comparative mapping of 10 cDNA clones of human chromosome 1 demonstrated that human chromosome 1 consisted of at least three segments homologous to Suncus chromosomes (chromosomes 7, 10, and 14). This approach with the direct R-banding FISH method is useful for constructing comparative maps between human and insectivore species and for explicating the process of chromosomal rearrangements during the evolution of mammals.

Running hamster: a new type of mutant characterized as speedy, rotative running without motor and balance deficits

Running hamster OYC (RHO) is a mutant spontaneously arisen in a closed colony of Armenian Hamsters and has a characteristic of speedy, rotative running behavior. There are several reports which describe such mutants as abnormal walking behavior in rodents due to ataxia or balance deficits. In this report, we describe results of several motor and balance tests in order to clarify whether or not RHO mutants have such disorders. RHO mutants showed no sign of either motor or auditory deficits, and scarcely had balance deficits tested. The animals only had slight head tilting at the starting of running. These results suggest that RHO is a really new type of mutant which has not previously been reported.