Heterozygosis and the behaviour of mice in two environments
Başlık:
Heterozygosis and the behaviour of mice in two environments
Yazar:
Smart, James L., author.
ISBN:
9780438058651
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (331 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: S. A. Barnett.
Özet:
Hybrid animals have often been found to behave differently from inbred, but the behaviour studied has usually had only an indirect bearing on fitness. An attempt has been made to study the effect of heterozygosis on the maternal behaviour, trial-and-error behaviour and daily activity of mice. Maternal behaviour: Observations were made at 21°C and -3°C on the responsiveness of females to four of their own young removed from the nest. Mice were observed five, six and seven days after the birth of their first and second litters. Four inbred strains (A, A2G, C57BL and GFF), all twelve possible first- generation crosses between them, and random-bred mice were used in the warm environment. Reciprocal crosses did not differ consistently on any measure. Hence there was no evidence of a maternal effect. C57BL, A2G and C57BL x A2G mice, all born and reared at -3°C, were watched in the cold. hybrid mice usually started to retrieve more promptly, spent less time carrying their young and completed retrieving more quickly than inbred mice. But C57BL mice retrieved their young as efficiently as F1 mice derived from them. Therefore, the heterotic retrieving of the other F1 hybrids was probably due to the sheltering of deleterious alleles with recessive effects, and not to heterozygosis per se. F1 mice tended to repair their nests more readily than inbred mice, and to rear on their hind legs in exploration more often. Random-bred mice spent less time carrying their young and repaired their nests more promptly than inbred and F1 mice. Hence, selection for these charateris-tics in the breeding of the random-bred mice is probable. There was a marked positive correlation between maternal retrieving efficiency and survival of young at -3°C. It is therefore tentatively suggested that the maternal behaviour of hybrid mice is an example of behavioural euheterosis. Cold tended to slow down all activities. No behaviour pattern was elicited as promptly or as often at -3°C as at 21°C. There was also evidence of genotype-environment interaction; for instance, nest-building by F1 mice was less affected by cold than that by inbred mice. With repeated experience of retrieving, mice both started to retrieve more promptly and also completed it more quickly, though there was no change in carrying time. The change was probably due to experience of retrieving, and not to habituation or to age of young. The results of tests with second litters suggest some retention of the habit of prompt retrieving over three weeks. Trial-and-error behaviour: The trial-and-error behaviour of male C57BL, A2G and C57BL X A2G mice was investigated in apparatus in which pressing a lever can release a pellet of food. A2G mice had the highest basic unrewarded pressing rate. C57BL mice learned to press the lever for food as readily as F1 mice and more readily than A2G mice, despite being slowest to start pressing the lever. Response rates rose as the frequency of reward was reduced from one pellet every press to one in fifty presses. Hybrid mice tended to perform more efficiently than their inbred parents on the one in five and one in ten schedules. The rate of pressing by A2G mice continued to increase on very low ratios of reward, but that of C57BL mice fell markedly. A2G mice tended to be the most efficient when restraint was rewarded (not pressing the lever during a delay before the arrival of the pellet), but their superiority disappeared on the longest delay. On extinction schedules, in which lever-pressing was no longer rewarded, the classes differed little. Over all, the hybrid mice were probably more efficient than either inbred parent strain. Activity For studying movement in a living space, a 'maze' was used with four arms radiating from a central nest box in which a mouse can live indefinitely. Movements were recorded automatically. C57BL, A2G and C57BL x A2G male mice were each kept alone for three days in these 'plus-mazes': one arm was empty, and food, water and balsa wood, respectively, were at the ends of the other three. Mice usually spent eight to ten hours per day out of the nest; they visited all arms almost equally frequently but spent most time in the food and balsa arms. Excursions into the arms declined after the first day, but time spent out of the nest remained fairly constant. C57BL mice made many more visits to the arms than A2G mice and remained longer out of the nest. Hybrid mice were intermediate between their parent strains on these measures, but resembled C57BL mice much more closely than A2G mice. Mice also differed in the way they apportioned their time. C57BL and F1 mice spent proportionally much less time in the food arm and much more in the balsa arm than A2G mice. Therefore the pattern and level of activity of C57BL mice in the plus-maze was partially dominant over that of A2G mice. Variation in behaviour in frequency of rearing during retrieving tests and in behaviour in the plus-maze, hybrid mice varied less than their inbred parents; but in retrieving latency and several measures of trial-and-error behaviour the results were equivocal.
Notlar:
School code: 0547
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684669.1) | 684669-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.