Allele mining in prolactin receptor gene and its association with some economic traits in Egyptian goat breeds.

The objectives of the current study were to identify polymorphism in the prolactin receptor (PRLR) gene among three Egyptian goat breeds (Zaraibi, Damascus, and Barki) and to investigate the association between PRLR genotype, parity, season of kidding, and litter size factors with milk yield and reproductive traits of Zaraibi goats. One hundred and ninety blood samples were collected for DNA extraction, with 110 from Zaraibi, 40 from Barki, and 40 from Damascus breeds. Three genotypes, CC, CT and TT, for the prolactin receptor gene were identified in the 190 DNA samples using restriction fragment length polymorphism and were confirmed by direct sequencing technique. Milk yield during suckling and lactation periods in addition to age at first conception, gestation length, and litter size were determined in 110 Zaraibi goats. The Zaraibi goats recorded the highest heterozygosity (0.495) and the effective number of alleles (1.972). The g.62130C > T SNP showed a significant association (p < 0.01) with suckling, lactation, and total milk yield of Zaraibi goats with the highest values recorded at the third parity. Age at the first conception and gestation length traits were significantly influenced by the kidding season (p < 0.05) with younger age in autumn and shorter length in spring seasons. Milk yield during the suckling period was significantly (p < 0.01) higher in the case of triplets' litter size. The current study showed that litter size and parity played an important role in the amount of Zaraibi goats' milk yield. The g.62130C > T SNP of the PRLR gene may be a useful marker for assisted selection programs to improve goat milk yield during suckling and lactation periods with the heterozygous genotype CT recording the highest values.

Genetic analysis of prolificacy, milk production and composition traits in Egyptian Zaraibi goats.

This study was conducted to genetically and environmentally characterize prolificacy (litter size and weight at birth; LSB and LWB and litter size and weight at weaning; LSW and LWW, respectively), milk yield at the 7th (MY7), 15th (MY15), 30th (MY30), 60th (MY60), 90th (MY90) day of lactation and monthly milk yield (MMY) and milk composition traits in Egyptian Zaraibi goats. A total of 443 and 421 records produced by 121 Zaraibi lactating goats were used to assess prolificacy and milk production traits, respectively. The milk composition traits were measured using 371 milk samples obtained at random from 53 goats. The fourth parity showed the highest values for LWB, LWW, and MMY (3.62, 18.15, and 28.99 kg, respectively). Milk composition traits revealed an inverse tendency, decreasing until the second month and then increasing until the seventh month. The heritability estimates ranged from 0.07 to 0.13, from 0.04 to 0.39, and from 0.07 to 0.33 for prolificacy, milk yield, and milk composition traits, respectively. Negatively high genetic correlations between MMY and all milk composition traits were found. MMY had the highest estimate of heritability (0.39 ± 0.07), this means that the genetic improvement of this trait could be achieved through direct selection.

Association of ß-casein gene polymorphism with milk composition traits of Egyptian Maghrebi camels (Camelus dromedarius).

The objectives of this study were to detect the polymorphism of 2126 A / G SNP in the ß -casein (CSN2) gene among Egyptian Maghrebi camels and to investigate the association of 2126 A / G SNP genotypes, parity, lactation stage, and temperature-humidity index (THI) with the milk composition traits of Maghrebi camels. Sixty-eight hair samples were collected from three different populations of Maghrebi camels for DNA extraction. Fat, protein, total solids, solids-not-fat, and lactose percentages were determined in Maghrebi camel milk using an automatic milk analyzer device. Three different genotypes - A/A, A/G, and G/G - were identified in the 5 ' flanking region of ß -casein gene by using PCR-RFLP method with the A/G genotype showing the highest frequency. Association among these three genotypes with milk composition traits suggests a positive effect of A/A genotype on acidity and protein percentage. Higher protein and acidity values were observed in the milk of individuals carrying the A/A genotype. The protein percentage of this study significantly increased from the first till the fourth parity and then decreased. Fat and total solid percentages were significantly higher in the late stage of lactation, while lactose showed a decreasing trend from the early till the late stages of lactation. Fat and protein percentages were highest in the low THI class. Our results encourage the utilization of Maghrebi camel milk for cheese and butter processing at the late lactation stages of the middle parities of their productive life. Moreover, the A/G SNP of the CSN2 gene may be used as a DNA marker in selection programs for the improvement of camel milk composition. Further studies are needed in order to fully explore the variation in the chemical composition of camel milk due to the effect of CSN2 gene, parity, lactation stage, and THI factors.

Polymorphism of lactoferrin gene in Egyptian goats and its association with milk composition traits in Zaraibi breed.

The objectives of this study were to identify polymorphisms in the lactoferrin gene among three Egyptian goat breeds (Barki, Zaraibi, and Damascus) and to investigate the effect of LF genotype, parity, and lactation stage on milk composition traits of Zaraibi goats. One hundred and thirty-two blood samples were collected for DNA extraction, with 53 from Zaraibi, 40 from Damascus, and 39 from Barki breeds. Fat, protein, total solids, solids-not-fat, and lactose percentages were determined in Zaraibi goat milk using an automatic milk analyzer. Two genotypes, GG and GA, in the lactoferrin gene were identified using single-strand conformation polymorphism and were confirmed by direct sequencing technique. The Zaraibi breed recorded the highest heterozygosity (0.272) and effective number of alleles (1.369), while the Damascus breed recorded the lowest values. The G/A SNP showed a significant association with protein, solids-not-fat, and total solid content of Zaraibi goat milk. Protein, solids-not-fat, and total solid content in our study were significantly higher at early and late parities. Lactose percentage decreased significantly from early to late parity. Fat, protein, solids-not-fat, and total solid content were significantly higher at early and late stages of lactation, and our results encourage the utilization of Zaraibi goat milk in cheese and butter processing at these stages. Moreover, the G/A SNP of the LF gene may be a useful marker for assisted selection programs to improve goat milk composition.

Genetic characterization of 11 microsatellite loci in Egyptian pigeons (Columba livia domestica) and their cross-species amplification in other Columbidae populations.

AIM: This study aimed to analyze the genetic diversity and relationships of 10 Egyptian pigeon populations belonging to Columba livia domestica speciesusing 11 microsatellite markers and to investigate the success of these markers amplification across another eight pigeon species. METHODS: Genomic DNA was isolated from feather samples of179 pigeon samples from 10 Egyptian breeds: Asfer Weraq (n=14), Austoraly (n=20), Reehani (n=21), Messawed (n=17), Nemssawy (n=27), Otatti (n=12), Morasla (n=17), Tumbler (n=22), Halaby Asfer (n=10), and Karakandy (n=19) in addition to Japanese feral pigeons (n=30). Genotyping was done using 11 specific polymorphic microsatellite makers. Moreover, 37 samples not belonging to C. livia domestica but belonging to another eight pigeon species were genotyped. The polymerase chain reaction (PCR) products were electrophoresed on an ABI 3130xl DNA Sequencer. The basic measures of genetic diversity and phylogenetic trees were computed using bioinformatics software. RESULTS: Across the 10 studied Egyptian populations, the number of alleles per locus ranged from 3 to 19 and the average number of alleles observed was 9.091. The lowest value of expected heterozygosity (0.373) was obtained for the Reehani breed, and the highest value (0.706) was found for Morasla breed. The overall expected heterozygosity of Egyptian pigeons was 0.548. The FST coefficient which indicates fixation coefficients of subpopulations within the total population for the 11 loci varied from 0.318 to 0.114 with a relatively high mean (0.226). In our study, the FIS showed a relatively high average(0.037). The pairwise Reynolds's genetic distance between the11 studied pigeon populations recorded lower values between Otatti and Austoraly (0.025) and between Morasla and Japanese feral pigeons (0.054). These results are supported by clustering pattern either by the neighbor-joining phylogenetic tree or by a Bayesian clustering of STRUCTURE with the admixture method. CONCLUSIONS: We confirm the applicability of the CliµD17, CliµT17, CliµD16, CliµD32, CliµT13, CliµD01, PG1, PG2, PG4, PG6, and PG7 microsatellite markers among Egyptian domestic pigeons and across other pigeon species using cross-species amplification method. The information from this study should be useful for genetic characterization and for developing conservation programs of this important species.

The association between glutamine repeats in the androgen receptor gene and personality traits in dromedary camel (Camelus dromedarius).

Temperament traits such as fearfulness are important as they define an animal's responses to its environment and handling. The increasing automation of daily tasks and growing population limits contact between camels and humans. Such limitations contribute to fear of humans and changes in physical environment. Monoamine oxidase A (MAOA) and androgen receptor (AR) genes are important candidates associated with mammal personality. In our analysis, MAOA exon 15 showed no polymorphism but a novel polymorphism was seen in the camel AR exon 1; 16, 17, 18, and 19 glutamine repeats were detected. We genotyped 138 camels belonging to four Egyptian breeds: Maghrabi (n = 90), Sudani (n = 15), Somali (n = 23), and Baladi (n = 10) for AR. Out of the 90 genotyped Maghrabi camels, we evaluated responses of 33 and 32 mature females to a novel object and exposure to an unfamiliar person, respectively. AR gene showed a significant association based on the principal component (PC) score, which indicated the fear of human touch, and the PC score indicates fear during interaction with novel objects. Individuals carrying a shorter genotype in homozygote (S/S) were found to be more fearful. Furthermore, we found that Sudani and Somali breeds had a higher frequency of shorter genotype (S/S), which was associated with increased fearfulness. These findings reflect the behavioral tendency and consequently, affect the use of this breed. This is the first report showing the role of AR glutamine repeats influencing a behavioral trait in dromedary camels and leading to inter-breed differences. Fear-related traits reported here are important because camels cope with various types of stresses and fear, resulting from the demands of intensive production systems and racing events. However, further studies, employing functional genomics and linkage analysis are necessary for confirming the relationship between fearfulness and genetic variation.

Genetic polymorphism in melatonin receptor 1A and arylalkylamine N-acetyltransferase and its impact on seasonal reproduction in Egyptian sheep breeds.

This study was carried out to detect polymorphisms in the melatonin receptor 1A (MTNR1A) and arylalkylamine N-acetyltransferase (AA-NAT) genes and their association with reproductive traits. Blood samples of 126 animals from three Egyptian sheep breeds were collected. DNA was extracted and subjected to PCR restriction fragment length polymorphism (RFLP) analysis using the RsaI and SmaI enzymes. Two alleles (C and T) and three genotypes (CC, CT and TT) for MTNR1A and for AA-NAT (A and G; GG, GA and AA) were detected. The alleles C and A and the genotypes CT and GA showed the highest frequencies for the MTNR1A and AA-NAT genes, respectively. Association analysis of the MTNR1A single nucleotide polymorphism (SNP) with ewe reproductive traits revealed significant associations in the Ossimi and Rahmani breeds with age at first lambing, and the C allele seemed to be the favorable allele. The results for the AA-NAT SNP demonstrated significant correlations in Ossimi with age at first lambing and litter size and in Rahmani with lambing interval; the G allele seemed to be the desirable allele. In the first conception season, ewes carrying CT exhibited a significantly lower age of first lambing in the unfavorable season. Additionally, GG ewes exhibited a significantly lower age of first lambing in the early favorable season, followed by the unfavorable season. To the best of our knowledge, this is the first study of these associations in Egyptian sheep breeds. In conclusion, the polymorphisms revealed in this study could be used as genetic markers to improve reproductive efficiency during the unfavorable season, and the obtained desirable genotypes could be considered in new genetic selection schemes.