Morphogenetic studies of the rabbit. XXXIX. Ponderal correlation coefficients of the bones form two races of rabbitsкод для вставкиСкачать
Morphogenetic Studies of the Rabbit XXXIX. PONDERAL CORRELATION COEFFICIENTS OF THE BONES FROM TWO RACES OF RABBITS HOMER B. LATIMER AND PAUL B. SAWIN Department of Anatomy, Uniaersity of Kansas, Lawrence, and The Jackson Lahoratoq, Bar Harbor, Maine ABSTRACT Thirty-five male a n 30 female rabbits of large race 111 derived from the New Zealand White race and the same numbers of small race X, from Castle's small race, were used i n this study. Earlier studies on these two races have shown that the males are more variable in body weight and body length; and that the individual bones are likewise more variable in weight and in length in the males. In this study, body weight and the weight of the entire skeleton were correlated on the basis of the null hypothesis with the individual bone weights and the individual bone weights were intcrcorrelated. The correlations are, for the most part, higher in the males than in the females of both races. The males of small race X have higher correlations than the males of large race 111. Thus, although the entire body size varies more in the males. the weights of the bones are, €or the most part, more closely correlated with body weight and total skeletal weight and with the other bones in the males than in the females. Some of the lowest correlations are with bones having large proportions of cancellous bone. Earlier studies of large race 111 and small race X rabbits from The Jackson Laboratory at Bar Harbor, Maine, have shown that the males are more variable than the females in bvdy weight, body length, and also in the weights and linear measurements of most of the bones (Latimer and Sawin, '57, '59, '62, '63). With this in mind, in the present study, coefficients of correlation between net body weight, the weight of the entire skeleton, and the separate bones have been determined. MATERIALS AND METHODS The 35 male and 30 female adult rabbits of race 111, derived from the New Zealand White race, and the 35 male and 30 female animals of normal race X (age about 5 months to 2 years), derived from Castle's small race, are the same as reported by Latimer and Sawin ('55, '63). These were all raised under similar conditions at The Jackson Laboratory. They were shipped to Kansas where they were sacrificed and studied by one person (H.B. L.), who is also responsible for the preparation of these data. The methds used in studying these skeletons are described in detail in an earlier publication (Latimer and Sawin, '62). ANAT. REC., 159: 29-32. RESULTS Correlations of weights of indiuidual hones with net body weight. The coefficients of correlation between net body weight and the weight of the entire skeleton and ten bones or pairs of bones in both sexes of both races are shown in table 1. The net body weight is the gross body weight minus the contents of the digestive TABLE 1 Coefticients of correlation hetzceen net body weight and the entire skeleton and the weicrhts of individual bones, cr pairs o f hones Race 111 LMales Females Skeleton Mandible Sacrum Clavicle Scapula Humerus Radius and ulna 0s coxae Femur Tibia and fibula Calcaneus Race X Malcs Females 0.888 0.633 0.888 0.854 0.816 0.702 0.867 0.864 0.852 0.662 0.796 0.572 0.781 0.807 0.697 0.634 0.712 0.529 0.631 0.542 0.793 0.800 0.805 0.726 0.820 0.824 0.744 0.746 0.502 0.455 0.802 0.767 0.742 0.720 0.847 0.699 0.741 0.609 0.775 0.808 0.654 0.498 0.201 0.264 All weights are in grams. Correlations in of 0.325 and above arc significant at the and 0.418 and above are significant at the The corresponding values for the fqmales and 0.449. All correlations are positive. the 5% 1% are malcs level, level. 0.349 29 30 HOMER B. LATIMER AND PAUL R . SAWIN tube and all dissectable fat (Latimer and Sawin, '55). The radius and ulna are usually ankylosed and the tibia and fibula are firmly ankylosed in the rabbit and hence these pairs of bones were weighed together. The weights of all paired bones are the sums of the weights of right and left bones of a pair. All of the correlations are positive and hence the signs are omitted in all of these tables. On the basis of the null hypothesis, all of the correlations in table 1 are significant at the 1% level except two, namely, those with the weights of sacrum and clavicle in the females of race 111. The correlations are somewhat higher in all cases in the males compared with the females, except for the scapula in race 111and the 0s coxae and femur in race X rabbits. The coefficients of variation of the clavicle, scapula, and 0s coxae are the three highest coeficients of variation in both sexes of race I11 and they are also very high in race X (Latimer and Sawin, '62, '63). This may account, in part at least, for the low correlations in this table. Not only are the correlations generally somewhat higher in the males than in the females, but the correlations in both sexes in race X are variably higher than in race 111, with one exception, namely, the scapula, which has a higher correlation in race I11 than in race X females. Thus the males of both races have higher correlations than the females, and the rabbits of the same sex generally have higher correlations in the smaller and more active race X rabbits. Correlutions of weights of individual bones with total skeletal weight. The correlation coefficients between skeletal weight and the weights of individual bones, or pairs of bones, are shown in table 2. All of these correlations are significant at the 1% level except that of the female clavicle in race X. In race 111, the correlations are higher in the males with two exceptions, namely, scapula and combined radius and ulna. In race X, however, there are only three bones with higher correlations in the males. These higher correlations in the females of race X compared with the males are unexpected and no explanation for this is immediately apparent, unless it is due to the lesser vari- TABLE 2 Coefficients of correlation between total skeletal weight and t h e weights o f t h e individual bones, or pairs of bones Race 111 Mandible Sacrum Clavicle Scapula Humerus Radius and ulda 0 s coxae Femur Tibia and fibula Calcaneus Race X Males FemaIes Male4 Females 0.897 0.838 0.711 0.695 0.962 0.793 0.479 0.601 0.850 0.950 0.966 0.911 0.592 0.791 0.939 0.928 0.937 0.408 0.662 0.954 0.866 0,906 0.911 0.897 0.890 0.878 0.932 0.902 0.918 0.972 0.967 0.981 0.913 0.883 0.853 0.840 0.921 0.892 0.948 0.930 1\11 weights are in grams. All of the corrclations arc positive and the significances of these are the same as i n table 1. ability in total skeletal weight in these race X females (Latimer and Sawin, '63). The correlations in race X compared with the same sex of race I11 rabbits are higher, except in the male clavicle, humerus, and os eoxae and the female clavicle and scapula. Thus, with certain exceptions. the parts of the skeleton are generally better correlated with total skeletal weight, as well as with net body weight, in the smaller race X rabbits. AS one might expect, these correlations with skeletal weight are higher than with body weight, except that of the scapula in both sexes of both races and the clavicles in male and female race X rabbits. The higher correlations between the weight of the scapula and body weight in all of these populations is rather puz7ling. One would expect that all of the bones of the skeleton would be more closely related to the total skeletal weight than to net body weight. Correlations between weights of indivitlual bones. The correlation coefficients between the weights of the individual bones and body and skeletal weight have been shown in tables 1 and 2, and now the coefficients of correlation between the weights of these bones, or pairs of bones, are presented in table 3 for the males and females of race 111. On the basis of the null hypothesis, all of the correlations for the males are significant at 1%, while in the females one correlation is not significant and four are significant only at the 5% level. All of these correlations below 31 CORRELATIONS OF RABBIT BONES TABLE 3 Coefzients of correlation between the weights of some of the individual bones of race III rabbits Mandible Mandible Sacrum Sacpula Humerus Radius and ulna 0 s coxae Femur Tibia and fibula Calcaneus Sacrum Scapula Humerus 0.658 0.393 0.948 Radius and I_._-~ i l n-i 0.660 0.442 0.852 0.842 cgacFemur Tibia and fibula Calcaneus 0.502 0.433 0.777 0.835 0.498 0.557 0.749 0.869 0.465 0.613 0.728 0.820 0.551 0.477 0.572 0.629 0.699 0.752 0.954 0.822 0.806 0.942 0.721 0.764 0.892 0.351 0.730 0.725 0.767 0.672 0.341 0,660 0.884 0.878 0.622 0.853 0.700 0.755 0.530 0.927 0.732 0.965 0.723 0.899 0.912 0.903 0.744 0.862 0.914 0.677 0.696 0.920 0.947 0.707 0.716 0.882 0.882 0.885 0.866 0.799 0.811 0.929 0.797 0.838 0.916 Correlations for the fcmales are in the upper right half, and for the males $ the lower Ieft half of the table. All correlations are positive and the slgnificances of these are the same as m table 1. TABLE 4 Coefficients of correlation between the weights of some of the bones of race X rabbits Mandible Mandible Sacrum Scapula Humerus Radius and ulna 0 s coxae Femur Tibia and fibula Calcaneus Sacrum Scapula Radius and ulna ,Zae Femur Tibia and fibula calcaneus 0.780 0.407 0.821 0.849 0.793 0.890 0.868 0.810 0.911 0.927 0,894 0.795 0.868 0.854 0.933 0.813 0.594 0.844 0.903 0.762 0.753 0.799 0.867 0.907 0.867 0.937 0.935 0.921 0.956 0.908 0.860 0.925 0.976 0.934 0.918 Humerus 0.751 0.789 0.900 0.880 0.772 0.886 0,826 0.866 0.939 0.864 0.866 0.823 0.813 0.788 0.865 0.937 0.888 0.882 0.952 0.884 0.962 0.908 0.939 0.896 0.815 0.764 0.699 0.872 0.893 0.893* 0.941 0.918 0.944 0.932 0.909 0.857 0.949 The Correlations for. the females are in the upper right half, and for the males in the lower left half of the table. All correlabons are positive and the significances of these are the same as in table 1. the 1% level of significance are correlations with the sacrum. Table 1 shows that the female sacrum is not significantly correlated with body weight, and, although it is significantly correlated with total skeletal weight (table 2 ) , it is the lowest correlation of all of the bones in the female. The only bones significantly correlated at the 1% level with the female sacrum are femur, tibia plus fibula and calcaneus, or the bones of the hind limb. Table 4 presents the coefficients of correlation for the male and female bones of race X rabbits. AII of the correlations for the males of race X are significant at 1% as they were for the race I11 males. In race X females, all of the correlations are significant at 1% except one, that between sacrum and humerus, which is significant only at the 5% level. Thirty of the 36 correlations are somewhat higher in the males of race X com- pared with race 111 males. Three of the six correlations which are lower in race X males than in race 111 males are correlations with the sacrum and three are with the 0 s coxae. In the females of the two races there are only three correlations higher in race TI1 than in race X. Two of these correlations are with the sacrum and one is with the 0s coxae. The sacrum has some low correlations with the other bones in tables 3 and 4, and this may be due to its very high variability in weight. In race X it is the most variable in weight of all of the bones, and in race I11 it is one of the most variable bones (Latimer and Sawin, '63). Ingalls ('31) found that the human sacrum has the highest variability; and second in variability is the sternum. He suggested that the high variability of these bones may be due to their very large proportion of cancellous bone. Our observations on these rabbit 32 HOMER B. LATIMER AND PAUL B. SAWIN bones seem in accord with this suggested explanation. Shape of the sacrum may be a factor also. We need further study to learn if there are other factors operating to cause this high variability and these low coefficients of correlation. ACKNOWLEDGMENTS This investigation was supported by Public Health Service Research Grants CA00281 from the National Cancer Institute, HD-01496 from the National Institute of Child Health and Human Development, and FR-00251 from the Division of Research Facilities and Resources, and in part by Research Grant E-40 from the American Cancer Society. The final draft of this manuscript was made possible through the efforts of Mrs. Homer Latimer and Dr. E. W. Lowrance. LITERATURE CITED Ingalls, N. W. 1931 Observations on bone weights. Am. J. Anat., 48: 45-98. L a t h e r , H. B., and P. B. Sawin 1955 Morphogenetic studies of the rabbit. XII. Organ size in relation to body weights in adults of small sized race X. Anat. Rec., 123: 81-102. 1957 Morphogenetic studies of the rabbit. XIX. Organ size in relation to body size in large race 111 and in small race X. Anat. Rec., 129: 457-472. 1959 Morphogenetic studies of the rabbit. XXII. Linear measurements of large race I11 and small race X. Anat. Rec., 134: 69-86. 1962 Morphogenetic studies of the rabbit. XXXI. Weights and linear measurements of some of the bones of 65 race I11 rabbits. Am. J. Anat., 110: 259-268. 1963 Morphogenetic studies of the rabbit. XXXIV. Weights and linear measurements of the bones of small race X rabbits compared with large race 111. Am, J. Anat., 113: 235-243.