115
Notes Literature Cited 1. ANEJA, S. and C.K. ATAL. Plantlet formation in tissue cultures from lignotubers of Eucalyptus citriodora Hook. Current Sci. 38:69. 1969. 2. MEHRA, A. and P.N. MEHRA. Organogenesis and plantlet
formation in vitro in almond. Bot. Gaz. 135:61-73. 1974. 3. MURASHIGE, T. and F. SKOOG. A revised medium for
rapid growth and bioassays with tobacco tissue cultures. Physiol. Plantarium 15:473-497. 1962. 4. SCHENK,
R.V.
and
A.C.
HILDEBRANDT.
Medium
and
technique for induction and growth of monocotyledonous and dicotyledonous plant cell cultures. Can. J. Botany 50 199:204. 1972. 5. WINTON, L. Plantlets from aspen tissue cultures. Science 160:1234-1235. 1968. 6. . Tissue culture propagation of European aspen. Forest Sci. 17:48-50. 1971.
Spontaneous seizures: A new mutation in Syrian golden hamsters C. H. Y O O N , J. S. PETERSON, AND D. CORROW
PONTANEOUS motor seizures with tonic muscle spasms and severe paralytic states have been obS served in inbred line BIO® 86.93 of Syrian hamsters (Mesocricetus auratus auratus). These animals had been inbred for 23 generations and maintained by BioResearch Consultants. The seizures, which last from 2 to 5 hours, can be precipitated by mild stress, and occur in animals between the ages of 30 days and 60 days. Breeding tests have shown that the condition is transmitted as a simple recessive; accordingly, the gene symbol sz is proposed for this condition. Methods and Materials Animals showing signs of seizure were mated inter se, and offspring were observed carefully once each week for any signs of seizure activity. A number of animals known to have seizures were outcrossed to animals from a normal inbred line—BIO® 4.22—that had been inbred for 54 generations and was The authors are affiliated, respectively, with the Department of Biology, Boston College, Chestnut Hill, Mass. 02167; Bio-Research Institute, and Bio-Research Consultants, 9 Commercial Ave., Cambridge, Mass. 02141. This work was supported in part by USPHS Research Grant NS-02267 (National Institute of Neurological Diseases and Stroke) to C. H. Yoon, and in part by General Research Support Grant SO1RR-05525 (Division of Research Facilities and Resources) to Bio-Research Institute. The Journal of Heredity 67:115-116. 1976.
unrelated to BIO 86.93. The F, animals produced from these crosses were observed for seizures and were then mated inter se to produce F 2 animals. The F 2 animals were also carefully observed for seizures. Seizures often occur when the animals as well as the cages containing them have not been moved or disturbed at all. However, the seizures appear to occur more often during the routine handling of animals, such as changing cages or replacing water bottles, than when they are left undisturbed in their cages. During seizures animals appear to go through more or less definable stages: the first stage includes mild prodromal signs; the second stage initiates tonic muscle spasms of the hind legs, and the third stage produces a totally paralytic state. Animals reaching the first stage always enter the second stage, but they do not always enter the third stage. Almost all young seizure animals (up to 30 days of age) were seen to enter stage 3, but older animals (45 to 60 days old) reached stage 2 only. All animals reaching stage 2 were classified as seizure animals.
Results Breeding data When animals known to have seizures were mated inter se, all of their offspring had seizures. When animals known to have seizures were outcrossed to animals from normal inbred line, BIO4.22, none of the F[ animals had seizures. However, when these F, animals were mated inter se, approximately one-quarter of the F2 animals had seizures. The distribution of males and females among affected animals was approximately equal. The data shown in Table I agree with the interpretation that seizure is a simple recessive trait. Description of seizures When placed in a new cage, it is typical of hamsters to move rapidly around the cage, exploring, digging, and trying to escape. This activity continues for some time in normal animals. However, in seizure hamsters a reduction in normal activity as well as obvious clumsiness can be noted after the first few minutes. The ears are held back tightly against the head and they walk with their heads and bodies held much lower to the cage floor than do normal animals. At this time, close observation reveals subtle and yet definite facial contortions: the lower lip quivers somewhat and is pulled downward, exposing the roots of the lower incisors in a very un-
Table I. F2 distribution from crosses between seizure and nonseizure animals. (Total number of matings was 8; total number of litters was 18)
Observed Expected*
Seizure
Nonseizure
Total
Y2
P
29 31.5
97 94.5
126 126
0.85
>0.05
Expected if seizure is a simple recessive trait
The Journal of Heredity
116
natural manner. These activities comprise stage I and last approximately 10 to 20 minutes. Then, the animals' clumsiness gives way to serious locomotor difficulty. They frequently fall and completely roll over, especially when trying to stand up on their hind legs. After this, the hind legs curl up and remain so for some time. Then the hind legs become extended outward in a tonic spasm (stage 2). At this time, however, the front legs are still functional and the animals often crawl around the cage dragging the hind legs. This stage may last 1 to 2 hours or even longer. At the third stage, both front and hind legs are in a rigid, quivering state. As shown in Figure 1, both front and hind legs are extended forward, with the body twisted, the tail curled upward, the ears held back, and the eyes rolled back and glassy. This third stage lasts for 20 to 40 minutes. Then the animals recover and usually FIGURE 1 — Hamster in a totally paralytic state. Note exrevert back to stage 2, where they may remain for 1-2 tension and rigidity of all 4 legs, with twisted body, curled tail, hours more, finally falling to sleep. It should be noted here that, at weaning, seizure and flattened ear pinnae. hamsters usually are smaller and thinner than their normal littermates. However, they outgrow this condition by about day 60, when seizure susceptibility disappears. In some rare instances, animals have been observed to have seizures after day 60, or even at day 90. This usually occurs in females when delivering a litter. animals and last from about 2 to 5 hours. The condition is a simple recessive trait, and the gene symbol Discussion sz is proposed. Hereditary seizures have been reported in a number Literature Cited of laboratory and domestic animals1"3-5'6. According to published descriptions, hamster seizures are very similar 1. ATKESON, F.W., H.L. IBSEN, and F. ELDRIDGE. Inherito those reported in fowl3 and in gerbils5, although tance of an epileptic type character in Brown Swiss cattle. they lack the violent myoclonic jerking seen in gerbils. J. Hered. 35:45-48. 1944. Also, hamster seizures differ from those in fowl and 2. BARKER, J. Epilepsy in the dog—a comparative approach. gerbils in that they are usually outgrown and cease by J. Small Anim. Pracl. 14:281-289. 1973. the age of about 60 days. Loud noises, buzzers, or 3. CRAWFORD, R.D. Epileptiform seizures in domestic painful stimuli have no noticeable effect on inducing fowl. J. Hered. 61:185-188. 1970. 4. GRUNEBURG, H. The Genetics of the Mouse. Martinus seizures. In that respect, they are quite distinct from Nijhoff, The Hague, p. 207-208. 1952. audiogenic seizures in mice4. 5. LOSKOTA, W.J., P. LOMAX, and S.T. RICH. The gerbil
Summary Hereditary spontaneous seizures in the Syrian hamster are described. The seizures occur in 30 to 60-day-old
as a model for the study of the epilepsies. Epilepsia 15:109119. 1974. 6. SAUNDERS, L.Z. A check list of hereditary and familial diseases of the central nervous system in domestic animals. Cornell Vet. 42:592-600. 1952.
Notes Literature Cited 1. ANEJA, S. and C.K. ATAL. Plantlet formation in tissue cultures from lignotubers of Eucalyptus citriodora Hook. Current Sci. 38:69. 1969. 2. MEHRA, A. and P.N. MEHRA. Organogenesis and plantlet
formation in vitro in almond. Bot. Gaz. 135:61-73. 1974. 3. MURASHIGE, T. and F. SKOOG. A revised medium for
rapid growth and bioassays with tobacco tissue cultures. Physiol. Plantarium 15:473-497. 1962. 4. SCHENK,
R.V.
and
A.C.
HILDEBRANDT.
Medium
and
technique for induction and growth of monocotyledonous and dicotyledonous plant cell cultures. Can. J. Botany 50 199:204. 1972. 5. WINTON, L. Plantlets from aspen tissue cultures. Science 160:1234-1235. 1968. 6. . Tissue culture propagation of European aspen. Forest Sci. 17:48-50. 1971.
Spontaneous seizures: A new mutation in Syrian golden hamsters C. H. Y O O N , J. S. PETERSON, AND D. CORROW
PONTANEOUS motor seizures with tonic muscle spasms and severe paralytic states have been obS served in inbred line BIO® 86.93 of Syrian hamsters (Mesocricetus auratus auratus). These animals had been inbred for 23 generations and maintained by BioResearch Consultants. The seizures, which last from 2 to 5 hours, can be precipitated by mild stress, and occur in animals between the ages of 30 days and 60 days. Breeding tests have shown that the condition is transmitted as a simple recessive; accordingly, the gene symbol sz is proposed for this condition. Methods and Materials Animals showing signs of seizure were mated inter se, and offspring were observed carefully once each week for any signs of seizure activity. A number of animals known to have seizures were outcrossed to animals from a normal inbred line—BIO® 4.22—that had been inbred for 54 generations and was The authors are affiliated, respectively, with the Department of Biology, Boston College, Chestnut Hill, Mass. 02167; Bio-Research Institute, and Bio-Research Consultants, 9 Commercial Ave., Cambridge, Mass. 02141. This work was supported in part by USPHS Research Grant NS-02267 (National Institute of Neurological Diseases and Stroke) to C. H. Yoon, and in part by General Research Support Grant SO1RR-05525 (Division of Research Facilities and Resources) to Bio-Research Institute. The Journal of Heredity 67:115-116. 1976.
unrelated to BIO 86.93. The F, animals produced from these crosses were observed for seizures and were then mated inter se to produce F 2 animals. The F 2 animals were also carefully observed for seizures. Seizures often occur when the animals as well as the cages containing them have not been moved or disturbed at all. However, the seizures appear to occur more often during the routine handling of animals, such as changing cages or replacing water bottles, than when they are left undisturbed in their cages. During seizures animals appear to go through more or less definable stages: the first stage includes mild prodromal signs; the second stage initiates tonic muscle spasms of the hind legs, and the third stage produces a totally paralytic state. Animals reaching the first stage always enter the second stage, but they do not always enter the third stage. Almost all young seizure animals (up to 30 days of age) were seen to enter stage 3, but older animals (45 to 60 days old) reached stage 2 only. All animals reaching stage 2 were classified as seizure animals.
Results Breeding data When animals known to have seizures were mated inter se, all of their offspring had seizures. When animals known to have seizures were outcrossed to animals from normal inbred line, BIO4.22, none of the F[ animals had seizures. However, when these F, animals were mated inter se, approximately one-quarter of the F2 animals had seizures. The distribution of males and females among affected animals was approximately equal. The data shown in Table I agree with the interpretation that seizure is a simple recessive trait. Description of seizures When placed in a new cage, it is typical of hamsters to move rapidly around the cage, exploring, digging, and trying to escape. This activity continues for some time in normal animals. However, in seizure hamsters a reduction in normal activity as well as obvious clumsiness can be noted after the first few minutes. The ears are held back tightly against the head and they walk with their heads and bodies held much lower to the cage floor than do normal animals. At this time, close observation reveals subtle and yet definite facial contortions: the lower lip quivers somewhat and is pulled downward, exposing the roots of the lower incisors in a very un-
Table I. F2 distribution from crosses between seizure and nonseizure animals. (Total number of matings was 8; total number of litters was 18)
Observed Expected*
Seizure
Nonseizure
Total
Y2
P
29 31.5
97 94.5
126 126
0.85
>0.05
Expected if seizure is a simple recessive trait
The Journal of Heredity
116
natural manner. These activities comprise stage I and last approximately 10 to 20 minutes. Then, the animals' clumsiness gives way to serious locomotor difficulty. They frequently fall and completely roll over, especially when trying to stand up on their hind legs. After this, the hind legs curl up and remain so for some time. Then the hind legs become extended outward in a tonic spasm (stage 2). At this time, however, the front legs are still functional and the animals often crawl around the cage dragging the hind legs. This stage may last 1 to 2 hours or even longer. At the third stage, both front and hind legs are in a rigid, quivering state. As shown in Figure 1, both front and hind legs are extended forward, with the body twisted, the tail curled upward, the ears held back, and the eyes rolled back and glassy. This third stage lasts for 20 to 40 minutes. Then the animals recover and usually FIGURE 1 — Hamster in a totally paralytic state. Note exrevert back to stage 2, where they may remain for 1-2 tension and rigidity of all 4 legs, with twisted body, curled tail, hours more, finally falling to sleep. It should be noted here that, at weaning, seizure and flattened ear pinnae. hamsters usually are smaller and thinner than their normal littermates. However, they outgrow this condition by about day 60, when seizure susceptibility disappears. In some rare instances, animals have been observed to have seizures after day 60, or even at day 90. This usually occurs in females when delivering a litter. animals and last from about 2 to 5 hours. The condition is a simple recessive trait, and the gene symbol Discussion sz is proposed. Hereditary seizures have been reported in a number Literature Cited of laboratory and domestic animals1"3-5'6. According to published descriptions, hamster seizures are very similar 1. ATKESON, F.W., H.L. IBSEN, and F. ELDRIDGE. Inherito those reported in fowl3 and in gerbils5, although tance of an epileptic type character in Brown Swiss cattle. they lack the violent myoclonic jerking seen in gerbils. J. Hered. 35:45-48. 1944. Also, hamster seizures differ from those in fowl and 2. BARKER, J. Epilepsy in the dog—a comparative approach. gerbils in that they are usually outgrown and cease by J. Small Anim. Pracl. 14:281-289. 1973. the age of about 60 days. Loud noises, buzzers, or 3. CRAWFORD, R.D. Epileptiform seizures in domestic painful stimuli have no noticeable effect on inducing fowl. J. Hered. 61:185-188. 1970. 4. GRUNEBURG, H. The Genetics of the Mouse. Martinus seizures. In that respect, they are quite distinct from Nijhoff, The Hague, p. 207-208. 1952. audiogenic seizures in mice4. 5. LOSKOTA, W.J., P. LOMAX, and S.T. RICH. The gerbil
Summary Hereditary spontaneous seizures in the Syrian hamster are described. The seizures occur in 30 to 60-day-old
as a model for the study of the epilepsies. Epilepsia 15:109119. 1974. 6. SAUNDERS, L.Z. A check list of hereditary and familial diseases of the central nervous system in domestic animals. Cornell Vet. 42:592-600. 1952.
