Modelling the growth curve and estimation of associated genetic parameters in Munjal sheep.

The study of growth curves in sheep is an effective approach to monitor the animal development for predicting the growth rate and improving overall flock performance. The purpose of the present work was to study the growth curve traits of Munjal sheep using different non-linear models and to estimate the genetic parameters of those traits for the possibility of inclusion of them under selection strategy. Total 2285 weight records at birth, 3, 6 and 12 months of age of 706 lambs born to 48 sires and 149 dams were collected from the registers maintained from 2004 to 2019. Various non-linear growth models viz., Brody, Gompertz, logistic, Bertalanffy and negative exponential were fitted to targeted growth curve traits and then evaluated using goodness of fit criteria such as adjusted R2, root means square error (RMSE), Akaike's information criterion (AIC) and Bayesian information criterion (BIC). The genetic parameters of growth curve traits were estimated using animal model. The results suggested that Brody model was best fitted to the data than other models. The growth curve estimates for mature weight (A), inflexion point (B) and rate of maturation (k) under Brody model were 25.82 ± 1.72, 0.84 ± 0.04, and 0.21 ± 0.04, respectively for female lambs, and 29.55 ± 2.04, 0.86 ± 0.03 and 0.19 ± 0.04, respectively for male lambs. The males showed superiority for mature weights whereas female lambs had higher maturation rates. The estimates of direct heritability for A, B and k were 0.33, 0.41 and 0.10, respectively. The moderate estimate of direct heritability of A and its negative genetic correlation with k indicated the scope of genetic improvement through selection based on mature weights. Therefore, it was concluded from the present findings that Brody model was the one that best describes the growth curve in the Munjal sheep and the selection based on mature weights can be employed for genetic improvement of Munjal flock.

Evaluation of physiological and morphological parameters for early prediction of prenatal litter size in goats.

The aim of the present study was to evaluate the physiological and morphological parameters of pregnant does for early prediction of prenatal litter size. In total, 33 does were screened using ultrasonography and further categorized into three groups based on does bearing twins (n = 12), a single fetus (n = 12), or non-pregnant does (n = 9). The rectal temperature °F (RT) and respiration rate (RR) as physiological parameters, while abdominal girth in cm (AG) and udder circumference in cm (UC) as morphological parameters were recorded at different gestation times, i.e. 118, 125, 132 and 140 days. In addition to this, age (years) and weight at service (kg) were also used. The statistical analyses included analysis of variance (ANOVA) and linear discriminant analysis (LDA). The results indicated that groups had significant (P < 0.05) differences among morphological parameters at each gestation time, with higher AG and UC in does bearing twins followed by a single fetus and non-pregnant does. However, both physiological parameters were non-significantly (P > 0.05) associated with litter size groups. It was also revealed that the studied parameters showed increasing trends over gestation time in single and twin fetus categories, but they were on par among non-pregnant does. The results of the LDA revealed that estimated function based on age, weight at service, RR, RT, AG and UC had greater (ranging from 75.00 to 91.70%) accuracy, sensitivity and specificity at different gestation times. It was concluded that using an estimated function, future pregnant does may be identified in advance for single or twin litter size, with greater accuracy.

Effect of BsaA I genotyped intronic SNP of leptin gene on production and reproduction traits in Indian dairy cattle.

In the present study, candidate single nucleotide polymorphism (SNP) g.92450765 G > A of leptin gene was explored for Bos indicus cattle with an aim to explore its possible effect on production and reproduction traits. The genotypic and allelic frequencies of BsaA 1 genotyped SNP g.92450765 G > A indicated the predominance of AG (0.65) genotyped Sahiwal cows in our studied population. The least-squares analysis showed a significant association (p < 0.05) of identified genetic variants with total milk yield (TMY) and 305 days milk yield (MY) (p < 0.05). The GG genotyped cows were found to be associated with higher milk yields. However, for reproduction traits under study AA genotype was found to be more favorable with respect to service period and calving interval (p < 0.05). Computational analysis was also performed to predict changes if any in the transcription factor binding sites (TFBS) caused due to the identified SNP in the intronic region of the leptin gene. TFBS analysis predicted that the targeted SNP at g.92450765G > A may lead to the disappearance of TFBS such as Hypermethylated in cancer 2 protein (HIC2), Max-binding protein MNT (MNT), Cyclic AMP-dependent transcription factor -3 (ATF3), Myc-associated factor X (MAX) and Microphthalmia-associated transcription factor (MITF). It may lead to changes in transcriptional regulation.

Neural network and Bayesian-based prediction of breeding values in Beetal goat.

The estimation of breeding values is prime concern for animal breeders in order to achieve desired genetic progress of farm animals. However, current methods for estimating BV involve simultaneous selection of animal model which are computationally intensive and time-consuming. The present attempt was made to predict breeding values of weaning trait under artificial neural networks (ANN), Bayesian technique (BT), and multiple regression (MR) methods. The data records comprising year of birth, sex, type of birth, dam's weight at kidding, birth weight, weaning weight, and estimated breeding values (BV) for weaning weight (under animal model) pertaining to 849 kids born to 37 sires and 237 dams between 2004 and 2019 were used in this study. All three methods, viz., ANN under multilayer perceptron (2 hidden layers), BT under Markov chain Monte Carlo (MCMC) approach, and MR under full model, were used for 75% training dataset initially and prediction model developed was applied on 25% test dataset. The initial analysis showed positive and significant (P < 0.01) relationship of BV with other variables which hinted that BV may be predicted with accuracy. Then, it was revealed from the results indicated that ANN, BT, and MR methods have similar accuracy (r = 0.86 to 0.87) for prediction of BV. However, ANN showed slightly higher but negligible model adequacy than BT and MR method. The prediction error under three methods was almost equal. The results indicated that these methods could be used as potential alternative for recurrent prediction of BV based on phenotypic data in order to optimize selection plans at young age in resourced population of Beetal goat.

Estimation of inbreeding and its effects on growth traits in Beetal goat.

The purpose of the present study was to estimate the inbreeding coefficient and its effects on various growth traits in Beetal goat using pedigree records of 963 kids born to 38 sires and 287 dams over the period of 2004 to 2019. The inbreeding coefficients for each individual were obtained under animal model. The effects of inbreeding along with other fixed effects such as year of birth, sex of kid, type of birth, and dam's weight at kidding on growth traits viz., weight at birth (BWT), 3 (WT3), 6 (WT6), 9 (WT9), and 12 (WT12) months of age were studied using least-squares analysis. Additionally, average daily gain and Kleiber ratio up to weaning age (90 days) were studied under the same model. The overall inbreeding coefficient was low in magnitude (1.42%) and ranged from 0 to 25% over the study period. The significant (P < 0.05) increase in average inbreeding coefficient (%) over the years was observed among the studied population. Although, the effects of various factors had significant (P < 0.05) influence on growth traits under least-squares model, the regression of targeted traits on inbreeding were non-significant (P > 0.05) and the same ranged from - 0.06 to 0.04. The present findings indicated that there was no inbreeding depression among the growth traits of Beetal goat. However, as inbreeding (%) raised in recent years only, the scientific efforts must be taken to avoid inbreeding at resourced population by introducing new germplasms at earliest.

Investigation of cause-specific pre-weaning mortality in Harnali sheep.

Lamb mortality is an important aspect in sheep production system which affects farm profitability worldwide. The aim of the present study was to investigate the causes of pre-weaning mortality (PWM) in Harnali lambs with respect to various associated factors. The data records of 173 lambs which died before 90 days of age (weaning age) out of 2057 lambs born during 2001-2020 year were collected from various registers, and the respective causes of mortality were taken from the post-mortem reports. The association of various factors such as age, sex, period of birth, birth weight of lamb and causes of death with PWM was assessed using chi-square test and log-linear modelling. The results showed that respiratory and digestive diseases were major causes of PWM. The log-linear modelling showed significant (P < 0.05) association of age, sex and period of birth with PWM. In the first month of age, digestive disease was the predominant cause of death; however, with age of lamb advances, respiratory disease was more prevalent. It was also revealed that male lambs (odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.24, 0.97) had lesser deaths due to respiratory diseases as compared to digestive disease. The reverse scenario was observed in female lambs. The findings of the present study might be helpful for understanding the risks and common causes of PWM in lambs to implement appropriate management practices in order to reduce economic losses to sheep farmers.

Meta-analysis of MspI derived variants of growth hormone gene associated with milk yield in dairy cattle.

OBJECTIVE: The present work aimed to obtain common effect sizes for the gene frequency and association of MspI derived variants of growth hormone (GH) gene with milk yield in dairy cows. METHODS: We performed a systematic review and meta-analysis of 35 published studies identified in literature search from 2000 to 2020 (n = 4164). These studies were specific to fragment size (329) for genotypes viz., CC (224, 105 bp), CD (329, 224, 105 bp) and DD (329 bp). Pooled standard mean differences (SMDs) as effect sizes between allele pairs were derived using different genetic models. The heterogeneity between effects sizes across studies was estimated using I2 Index (%). RESULTS: The common effect size for gene frequency of allele C (224, 105 bp) was significantly (P < 0.05) higher in 2881 Bos taurus/cross cows (0.82; 95% CI: 0.74, 0.89; I2 = 97.81%) than 1283 Bos indicus cows (0.15; 95% CI: 0.12, 0.18; I2 = 71.90%), with overall gene frequency was 0.33 (95% CI: 0.21, 0.46; I2 = 99.29%). Additive (CC vs. DD) and dominant (CC + CD vs. DD) did not revealed significant (P > 0.05) association with milk yield. However, completely over dominant (CC + DD vs. CD) and recessive (CC vs. CD + DD) models showed significant (P < 0.05) and positive SMDs with milk yield specially at early lactations. There was no evidence of heterogeneity (I2 = 0.00%) between SMDs across studies. CONCLUSIONS: This meta-analysis suggested potential association of C allele for enhancing milk production of dairy cows.

Evaluation of candidate point mutation of Kisspeptin 1 gene associated with litter size in Indian Goat breeds and its effect on transcription factor binding sites.

Kisspeptin gene (Kiss1) has a significant role in reproductive processes in mammals. However, only little information is available about the association of Kiss1 gene with litter size in Indian goat breeds. Thus, blood samples from 285 randomly selected animals were collected for DNA isolation and SNP profiling. The PCR product of 242 bp size harboring g.2540C>T mutation of Kiss1 gene was digested with the restriction enzyme Sac1. Least squares analysis revealed that Barbari goats showed significantly higher average litter size (2.86±0.08) compared to Beetal, Sirohi and Sojat breeds (P < 0.01). SNP locus g.2540C>T of Kiss1 gene also showed significant effect on litter size (P < 0.01). Goats with Genotype CT (2.66 ± 0.07) and TT (2.67 ± 0.26) had significantly higher (P < 0.01) litter size than CC (1.50 ± 0.05). From the transcription factor binding site analysis, it was predicted that due to g.2540C>T SNP, both native and mutant variant forms coded for putative binding sites for different transcription Factor. Allele T had putative binding sites for the androgen receptor which plays a significant role in the signaling pathway involved in increase in ovulation rate; which consequently can have a tremendous effect on average litter size.

Estimation of genetic parameters for early reproduction traits in Beetal goat.

The evaluation of early reproduction traits in Beetal goat was performed for possible effects of genetic and non-genetic factors on litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB), litter weight at weaning (LWW) and age at first kidding (AFK). The data records consisted of information of pedigree and targeted traits pertained to 223 does born to 25 sires and 122 dams between the years 2004 to 2019. A general linear model was used for assessment of non-genetic factors such as period of birth, type of birth and dam's weight at kidding on studied traits. Genetic evaluation of targeted traits was done to estimate variance components and genetic parameters under dyadic mixed modelling. The estimates of least-square means for LSB, LSW, LWB, LWW and AFK were observed as 1.27 ± 0.03, 1.25 ± 0.03, 3.24 ± 0.07 kg, 13.08 ± 0.30 kg and 27.56 ± 0.58 months, respectively. Only the period of birth showed significant (P < 0.05) effects for targeted traits in this study. The estimates of direct heritability for LSB, LSW, LWB, LWW and AFK were low in magnitude as 0.08, 0.03, 0.10, 0.03 and 0.06, respectively. The moderate to high genetic and phenotypic correlations among litter traits indicate simultaneous improvement for these traits. It was concluded that low ranged direct heritability estimates for targeted traits indicated modest scope for genetic improvement of reproductive efficiency in Beetal goat through selection and, therefore, adoption of improved managerial practices is necessary to improve reproductive efficiency of Beetal goat.

Meta-Analysis of Gene Polymorphism of Beta-Lactoglobulin Gene in Indian Dairy Cows.

The aim of the present paper was to summarize the gene polymorphisms of beta-lactoglobulin (BLG) gene and its effects on milk yield in 1840 genotyped Indian dairy cows reported in 17 published studies. The meta-analysis was undertaken using gene frequencies of individual studies under random effects model, whereas for association analysis of genotypes with milk yield, standardized mean differences (SMDs) along with 95% confidence interval (CI) were obtained under four genetic models such as additive (AA vs. BB), dominant (AA+AB vs. BB), completely over dominant (AA+BB vs. AB) and recessive (AA vs. AB+BB). The heterogeneity index (I2) was used to determine heterogeneity between studies. The results of meta-analysis suggested that the pooled allelic frequency of allele A was subsidiary as 0.29 (95% CI 0.24, 0.33, I2 = 88.54%) in targeted population, and also, it was non-significantly (P > 0.05) different between Bos indicus (0.28) and Bos taurus/cross cows (0.30). Egger's test indicated no risk of publication bias (P > 0.05). The results also revealed that BLG gene variants have non-significant (P > 0.05) association with milk yield under all genetic models. Although positive effects of SMDs under some models were observed, however, they failed to meet statistical significance (P > 0.05) due to high heterogeneity between studies which lead to conclusion of only uncertain influences of SNP genotypes with milk yield. It was concluded that BLG markers may not be beneficial for improving milk yield in Indian dairy cows. However, it is suggested that the revalidation of the present results should be done by using more number of studies.

Genetic and non-genetic effects associated with ewe productivity in Harnali sheep.

The objective of the current study was to estimate the genetic parameters for ewe productivity traits of Harnali sheep by examining non-genetic effects. The data records of 440 animals born to 85 sires and 259 dams were collected with respect to various traits such as litter size at birth (LSB), litter weight at birth (LWB), litter size at weaning (LSW), litter weight at weaning (LWW) and age at first lambing (AFL) for the period of 2001 to 2020. Genetic parameters were estimated by fitting a series of animal models using an average information restricted maximum likelihood (REML) algorithm in WOMBAT software. Least-squares analysis revealed significant (P < 0.05) influences of period of lambing, age and weight of ewe at lambing on the studied traits. These results indicated that heavier ewes had significantly higher (P < 0.05) values of litter weight traits than their counterparts. On the basis of likelihood ratio test, the estimates of direct heritability under best model for AFL, LSB, LWB, LSW and LWW were 0.06, 0.18, 0.09, 0.07 and 0.16, respectively. Maternal permanent environment effect made a significant contribution to the LSB trait (0.20). The genetic correlation between litter size and LWW was negative, while the remaining correlations were positive. The present results suggest that selection based on ewe productivity traits will result in low genetic progress and therefore the management role is more important for better gains.

Evaluating advanced computing techniques for predicting breeding values in Harnali sheep.

Advanced computing techniques have been used by animal researchers to understand the intricate data structures for deriving the most reliable allusions of populations in order to conserve genetically superior animals. The present attempt was made to evaluate the potential of two advanced techniques, artificial neural networks (ANN) and Bayesian technique (BT), for predicting breeding values (BV) of weaning weight (WWT) using data of 498 lambs born to 41 sires and 173 dams in Harnali sheep for the period from 2014 to 2019. The estimated BV for WWT was initially obtained using univariate animal model under restricted maximum likelihood procedure. ANN using multilayer perceptron with two hidden layers was fitted to training set (75%) of estimated BV to predict BV for test set (25%). Similarly, BT using Markov chain Monte Carlo (MCMC) method was also fitted to similar datasets. The high accuracy of prediction, i.e., correlation between BV and predicted BV, was observed as 0.89 and 0.90 under ANN and BT, respectively. Further, similar ranges of goodness of fit criteria, viz., R2, root mean square error (RMSE), mean absolute error (MAE), and bias, indicated that both ANN and BT had similar prediction ability, which was also confirmed by 10-fold cross-validation. The present study indicated high capability and analogous model adequacy for both techniques that can be exploited in selection programs.

Epigenetic status of buffalo fibroblasts treated with sodium butyrate a chromatin remodeling agent.

The somatic cells having higher levels of DNA methylation and reducing it in donor cells before nuclear transfer (NT) by treating them with chemicals, may improve cloning efficiency of NT embryos by providing donor cells with similar epigenetic characteristics as in vivo embryos. Therefore, the present study was planned to understand mechanism of epigenetic changes in donor cells (buffalo fibroblasts) treated with different concentration of sodium butyrate (NaBu)-a chromatin remodeling agent. The cultured fibroblasts purity and lineage were confirmed by fibroblast specific protein and gene markers (Vimentin, Tubulin and Cytokeratin) at different passages using immuno-staining and qPCR respectively. The buffalo fibroblast cells were treated with 1, 3 and 5 mM of NaBu and observations were taken on their morphological changes, population doubling time and cell proliferation after 48 h of treatment. The epigenetic changes were observed using acetylation (H3K9ac) and methylation (H3K27me3) markers expression. The fibroblast cells derived from new born ear tissue started emerging and anchoring to cell culture flasks within 24 h and showed spindle-shaped morphology. The confluent culture was cryopreserved at different time interval. The post thaw culture behavior of the cryopreserved cells was also observed at different time interval and passages. The morphology of NaBu treated cells were changed with increase of dosages of NaBu treatment. The increase population doubling times and decreases the proliferation rate in the dose dependent manner. The NaBu treatment showed that the significantly increased the acetylation (H3K9ac) and methylation (H3K27me3) level over the control. Based on the observations of fibroblast characterization as well as epigenetic modifications of these cells after treatment with NaBu, results suggest that the cells may provide a useful approach for better epigenetic reprogramming in SCNT embryos.

Effect of antioxidants supplementation on the quality of Beetal buck semen stored at 4°C.

AIM: An experiment was designed to evaluate the role of Vitamin E and glutathione in improving the seminal parameters during hypothermic storage of liquid semen at 4°C for 72 h. MATERIALS AND METHODS: Thirty-six semen ejaculates were collected by artificial vagina from 6 bucks (Beetal) during the normal reproduction season (September to November) at weekly interval. The samples were centrifuged, and the seminal plasma was removed. The sperm pellet was diluted with Tris-based extender and divided into three groups. Group T1: Control samples without antioxidants, Group T2: Samples supplemented with tocopherol at 3 mM, and Group T3: Samples supplemented with glutathione at 1 mM. The samples were evaluated for progressive motility, percent liveability, percent abnormal spermatozoa, and acrosome integrity after liquid preservation for 0, 24, 48, and 72 h. The level of lipid peroxidation and antioxidant enzymes, namely, glutathione peroxidase (GPx) and superoxide dismutase (SOD) were estimated after liquid preservation for 0 and 72 h. RESULTS: It was observed that, after storage of semen at 4°C up to 72 h, the progressive sperm motility, percent liveability, percent abnormal spermatozoa, and percent intact acrosomes were significantly (p<0.05) higher in group T2 and T3 samples as compared to control. However, the level of lipid peroxidation in T2 and T3 groups was significantly (p<0.05) lower after 72 h of incubation at 4°C. Similarly, GPx and SOD values were significantly (p<0.05) increased in T2 and T3 groups after 72 h of storage at 4°C. CONCLUSION: Thus, it can be concluded that Vitamin E and glutathione supplementation at 3 mM and 1 mM, respectively, while preserving the semen samples at 4°C helped in maintaining the seminal parameters up to 72 h and protected the spermatozoa from oxidative damage.

Effect of pasteurization of shell egg on its quality characteristics under ambient storage.

Three thermal processes viz. dry (55°C, 2 h), moist (57°C, 5 min) and microwave (power 9, 20 sec) were studied to determine their efficacy for the pasteurization of intact chicken eggs based on the extent of inactivation of artificially inoculated Salmonella typhimurium (ST) in the yolk of shell eggs and alteration in albumen protein solubility (APS). Moist heat treatment was superior to others as it brought about 2 log cfu/ml reduction of inoculated ST in much less time than dry heating but changes in APS were not significant. Subsequent quality evaluation of normal (uninoculated) eggs subjected to moist heat pasteurization during 15 days of ambient (35°C, 36% RH) (35 ± 0.5°C, 36 ± 2% RH)storage revealed no significant effect on percent loss in egg weight, albumen pH, viscosity of albumen and yolk and thiobarbituric acid values between pasteurized and unpasteurized eggs. Pasteurization had no adverse effect on foam volume and foam stability of albumen during storage in comparison to those of raw eggs. Naturally occurring aerobic mesophilic bacteria, coliforms, staphylococci, yeast and moulds on the egg shell surface and in egg contents got markedly reduced by pasteurization of shell eggs and their multiplication also retarded during storage. Both pasteurized and raw eggs remained fairly acceptable sensorily up to 10 days of storage at ambient conditions.

Homocysteine, lipid indices and antioxidants in patients with ischaemic heart disease from Maharashtra, India.

INTRODUCTION: Geographical and ethnic factors have recently been shown to have a significant role to play in cardiovascular diseases. The exact relationship between nutritional and geographical factors in cardiovascular diseases is not very clear. This study examined the relationship of hyperhomocysteinaemia with lipid profile and antioxidants in patients with ischaemic heart disease from rural areas in Maharashtra, India. METHODS: Blood cholesterol (total, high- and low-density lipoproteins cholesterol), triglycerides along with thiobarbituric acid reactive substances (TBARS), superoxide dismutase, glutathione peroxidase and catalase activities were measured in acute coronary syndrome (ACS) and chronic stable angina (CSA) patients from rural areas and in normal healthy controls from the same area. Plasma total homocysteine was measured by high pressure liquid chromatography with fluorescence detection. Folic acid and vitamin B12 were measured by chemiluminescence immunoassay. RESULTS: The relative lipid ratios were higher in the patients and had a poor correlation with antioxidants. Total homocysteine levels were significantly higher by almost three times more than the controls. TBARS levels also showed a similar pattern, whereas antioxidant enzymes showed a significantly greater fall in ACS than CSA. There was a definite inverse relationship between total homocysteine, TBARS and antioxidants in the patients. The levels of folic acid and vitamin B12 were 3-4 times higher in the patients compared to the controls. There was a poor correlation between the total homocysteine and vitamin levels in the patients. CONCLUSION: Blood homocysteine is a very important biomarker of cardiovascular diseases and must be evaluated along with other risk factors. There is a higher prevalence of hyperhomocysteinaemia in rural Indian patients. There appears to be a strong association of genetic factors in the development of ischaemic heart disease in Indian patients.

Relationship of plasma homocysteine with lipid profile parameters in ischemic heart disease.

The present study was undertaken to explore the relationship of plasma homocysteine with other biochemical parameters in ischemic heart disease. Plasma levels of total homocysteine was measured by HPLC-fluorescence detection with internal standard in 60 ischemic heart disease patients and were compared with 30 age matched normal healthy controls. The significant increase of plasma homocysteine was observed in both myocardial infarction and chronic stable ischemic heart disease patients when compared with the controls. The hyperhomocysteinemia appears be to due to increased body demand of vitamins such as folic acid, vitamin B(12), B(6), B(2) either alone or in combination to regulate normal homocysteine metabolism.

Prevalence of enterotoxigenic motile aeromonads in children, fish, milk and ice-cream and their public health significance.

Motile aeromonads, which have been implicated as causative agents of human gastroenteritis, meningitis. endocarditis and osteomyelitis, were isolated from fish, pasteurized and flavored milk and ice creams. Forty-five isolates of Aeromonas from diarrheic children (100) and 285 food samples comprising of fish (100), milk (85) and ice creams (100) were identified as A. hydrophila (21), A. sobria (16) and A. caviae (8). Five of these 45 isolates of Aeromonoas (3 A. sobria, 2 A. hydrophila) were from fecal samples of diarrheic children under five years of age. Twenty-six of these 45 isolates were found to be enterotoxin producing by ligated rabbit ileum loop technique. Isolation of enterotoxigenic motile aeromonads from food as well as diarrheic children have great public health significance which will be further discussed.

Karyotypic analysis of three species of Phasianidae (Galliformes: Aves).

The karyology of the partridges Francolinus francolinus asiae (2n = 70) and F. pondicerianus interpositus (2n = 68) and the Japanese quail Coturnix coturnix japonica (2n = 78) was investigated. The frequency distribution of the diploid number of chromosomes was tabulated and the most frequent number was taken to be the diploid number. All species showed a bimodal karyotype and the variation in the number of chromosomes was attributed to the macrochromosomes, although twelve macrochromosomes were present in all the species. Female heterogamety revealed that ZZ male:ZW female sex chromosome mechanism was present. The structure and behaviour of chromosomes during mitosis are described and the evolution of karyotype and cytotaxonomic considerations discussed.

Localization of NORs in spermatogonial metaphase chromosomes of six species of grasshoppers.

The silver staining technique was employed to locate Nucleolar Organiser Regions (NORs) in six species of grasshoppers viz. Aiolopus thalassinus F. (Tryxalinae); Oeodaleus abruptus Thunb., Gastrimargus transversus Thunb., Heteropternis respondens Walk. (Oedipodinae); Parahieroglyphus biliniatus Bol. and Spathosternum prasiniferum Walk. (Catantopinae). Usually the NORs were located on the larger elements of the chromosomal complement. However, in O. abruptus NORs were found on autosomes S8 and S9. The salient observations were: (1) NORs were seen in only a few of the several spermatogonial metaphases examined; (2) Active NORs were mostly located either on one chromatid of the homologues or on the homologue depicting heteromorphism; (3) NORs showed either proximal, subproximal or interstitial locations. However, in O. abruptus and P. bilineatus NORs were located at two positions. Distribution of NORs in different species and their probable role in tracing the evolutionary pathways in Acridoidea are discussed.