Hb Locus Research Articles

HAEMAGLOBIN TYPES IN SHEEP IN OF SEMI-ARID ZONE OF NORTH EASTERN NIGERIA

Genotyping is not a test to diagnose a disease, but rather a test looking for certain information encoded on the prion protein (PrP) gene. This encoded information helps determine the susceptibility of sampled sheep to developing clinical disease from a disease should the animal be exposed. Therefore, haemaglobin types in sheep in the semi-arid zone of North Eastern Nigeria was determined at haemoglobin (Hb) locus level. One hundred and sixty-eight (168) animals were used for the study. Blood samples comprising 56 each of Yankasa, Balami and Uda breeds were collected from households, sheep and goats’ markets and abattoir. The blood samples were analysed for haemaglobin types. Blood samples (5 mL per animal) were obtained from the jugular vein using a 10 mL syringe attached to 21gauge x ½ inch needle. The blood samples collected was then placed in tubes coated with ethylene-diamine tetra-acetic acid (EDTA) as anticoagulant. The samples were adequately labeled and taken to Federal Teaching Hospital Gombe haematology’s laboratory for analysis. Haemoglobin type was identified using cellulose acetate paper electrophoresis. Genotypic frequencies were estimated, and sheep showed only HbAA genotype. Genotypic frequencies were similar in both sexes of sheep implying that there was no effect in sex on Hb frequency. It is therefore concluded that there were no polymorphisms at Hb locus since only the Hb AA was exhibited.

Hemoglobin polymorphism and its association with morphometric and egg production traits in Ethiopian indigenous and Sasso chicken breeds.

The present study investigated the biochemical polymorphism of hemoglobin (Hb) and its relationship with performance traits of Ethiopian indigenous and Sasso chicken breeds. A total of 284 chickens reared in three agro-ecologies were examined for genetic diversity and associations with productive traits at Hb locus using agarose gel electrophoresis. The results showed that the HbA allele was dominant in both breeds, and a higher proportion of male chickens were HbAA genotypes, while females were predominantly HbBB types. In the highland agro-ecology, chickens with the HbAA genotype were the most dominant, whereas in mid- and low-land agro-ecologies, chickens with HbBB and HbAB genotypes were found to be more frequent. A moderate level of expected heterozygosity was obtained with 0.47 and 0.445 for indigenous and Sasso chickens, respectively, with an average effective number of alleles per locus of 1.89 and 1.80. Moreover, chickens with HbAA genotypes showed significantly (p ≤ 0.05) higher body weight and linear body measurements than those of HbAB and HbBB genotypes. However, for appendage body structures (comb and wattle dimensions), chickens with the HbAB and HbBB genotypes had higher mean values. Additionally, clutch size (14.2 ± 0.4), clutch length (21.8 ± 0.7), and eight-month egg production (84.1 ± 1.2) were significantly (p ≤ 0.05) higher for hens with HbBB genotypes, followed by those with HbAB-types. Therefore, the considerable hemoglobin variability and significant associations of Hb variants with the performance traits can be sought as guiding information for further genetic improvement interventions in the chicken breeds under investigation. Further microsatellite marker-based genotyping is recommended to validate the higher morphometric values for HbAA genotypes and the better egg production for HbBB and HbAB genotypes.

GENETIC DISI'ANCE MEASURES AMONG FIVE INDIGENOUS CATTLE BREEDS IN NIGERIA

Genetic variation is the basis of effective improvement in farm animals. Population differentiation is used for objective choice of parental genotypes that constitutes new hybrids in crossbreeding. In Nigeria, population characteristics of selected indigenous cattle breeds have not been fully documented. Therefore, blood protein electrophoretic patterns of selected indigenous cattle breeds in Nigeria were assessed. Blood samples (5mL) were taken underneath the tail by venipuncture from 200 cattle (40/breed) randomly selected from the five indigenous cattle breeds. The samples were subjected to cellulose acetate electrophoresis to determine the genetic variants of haemoglobin (Hb), carbonic anhydrase (CA) and transferrin (TO. Data were analysed using Euclidean genetic distance and cluster analysis. Two main clusters from the dendrogram were observed for each of Hb, CA and TE Euclidean genetic distance at the Hb locus between WF and SG, WF and RB, WF and BK, WF and Muturu were 15.3, 15.7, 23.9 and 35.1 respectively, while the corresponding values at CA locus were 3.9, 3.3, 29.1 and 36.2, similarly, the corresponding values at Tf locus were 22.8, 25.8, 94.3 and 102.7. Genetic distance estimates were found to be higher between non-related breeds than between breeds which had common ancestors.

Discrete cis-acting element regulates developmentally timed gene-lamina relocation and neural progenitor competence invivo.

SUMMARYThe nuclear lamina is typically associated with transcriptional silencing, and peripheral relocation of genes highly correlates with repression. However, the DNA sequences and proteins regulating gene-lamina interactions are largely unknown. Exploiting the developmentally timed hunchback gene movement to the lamina in Drosophila neuroblasts, we identified a 250 bp intronic element (IE) both necessary and sufficient for relocation. The IE can target a reporter transgene to the lamina and silence it. Endogenously, however, hunchback is already repressed prior to relocation. Instead, IE-mediated relocation confers a heritably silenced gene state refractory to activation in descendent neurons, which terminates neuroblast competence to specify early-born identity. Surprisingly, we found that the Polycomb group chromatin factors bind the IE and are required for lamina relocation, revealing a nuclear architectural role distinct from their well-known function in transcriptional repression. Together, our results uncover in vivo mechanisms underlying neuroblast competence and lamina association in heritable gene silencing.

Evaluation of haemoglobin variants of Red Sokoto goats and Yankasa sheep in Beji, Niger State, Nigeria: Effect on body weight and reproductive parameters

Blood was sampled from 76 Red Sokoto (RS) goats and 76 Yankasa Sheep (YS) to evaluate Haemoglobin (Hb) genotypes and their effect on body weight and some reproductive parameters of the animals. The blood samples were analyzed by cellulose acetate electrophoresis. The electrophoretic test revealed the presence of three co-dominant alleles (A, B and C) which produced four haemoglobin genotypes (AA, AB, BB andBC) in RS goats, and two codominantalleles (AandB) which gave rise to two haemoglobin genotypes (AA and AB) in YS. The frequencies of alleles A, B and C were 0.32, 0.61 and 0.07 in RS goats; and 0.945 and 0.055 for alleles A and B in YS. The estimated heterozygosities were 0.406 and 0.118 in RS goats and YS while the estimated inbreeding coefficients were 0.009 and 0.008 in the RS goats and YS, respectively. The observed and expected genotype frequencies deviated significantly from the expected Hardy-Weinberg equilibrium (P 0.05;chi-square=7.82for RS goats, P 0.01;chi-square = 13.13 for YS).There were significant (P<0.05) differences observed in the body weight of male YS as a result of the Hb type; individuals with Hb AB were observed to have higher body weight (44.00 kg) compared to those with Hb AA (22.83 kg).No significant (P>0.05) difference was observed however in the body weight of RS goats. Male YS with Hb AB had longer (P 0.05) scrotum (26.00 kg) and wider scrotal circumference (33.00 kg) compared to those with Hb AA (18.83kg;25.67kg,respectively). No significant (P>0.05) difference was however observed in there productive parameters of RS goats. It was concluded that polymorphism exist at the Hb locus in the YS and RS goats sampled in Beji and this had an influence on body weight and the reproductive parameters evaluated particularly in the sheep. More heterozygotes were also observed in the population studied there by leading to alow rate of in breeding coefficient in the animals.

An evolutionarily ancient mechanism for regulation of hemoglobin expression in vertebrate red cells

AbstractThe oxygen transport function of hemoglobin (HB) is thought to have arisen ∼500 million years ago, roughly coinciding with the divergence between jawless (Agnatha) and jawed (Gnathostomata) vertebrates. Intriguingly, extant HBs of jawless and jawed vertebrates were shown to have evolved twice, and independently, from different ancestral globin proteins. This raises the question of whether erythroid-specific expression of HB also evolved twice independently. In all jawed vertebrates studied to date, one of the HB gene clusters is linked to the widely expressed NPRL3 gene. Here we show that the nprl3-linked hb locus of a jawless vertebrate, the river lamprey (Lampetra fluviatilis), shares a range of structural and functional properties with the equivalent jawed vertebrate HB locus. Functional analysis demonstrates that an erythroid-specific enhancer is located in intron 7 of lamprey nprl3, which corresponds to the NPRL3 intron 7 MCS-R1 enhancer of jawed vertebrates. Collectively, our findings signify the presence of an nprl3-linked multiglobin gene locus, which contains a remote enhancer that drives globin expression in erythroid cells, before the divergence of jawless and jawed vertebrates. Different globin genes from this ancestral cluster evolved in the current NPRL3-linked HB genes in jawless and jawed vertebrates. This provides an explanation of the enigma of how, in different species, globin genes linked to the same adjacent gene could undergo convergent evolution.

Genetic diversity between exotic and Nigerian indigenous Turkey at different structural loci

Poultry genetic resources in general are considered to be the most endangered and under-conserved, detailed attention is therefore needed on the existing genetic resources to reduce or prevent the increasing genetic erosion of local livestock. This study was conducted to characterize and estimate genetic diversity in Nigerian indigenous turkey and exotic turkey using blood proteins (Haemoglobin, Transferrin and Albumin) and enzyme (Carbonic Anhydrase and Esterase 1) markers. A total of 110 turkeys comprising 50 Nigerian indigenous turkeys and 60 exotic turkeys were used for the analysis. Separation of blood protein genotypes was achieved using cellulose acetate electrophoresis. The populations were characterized for their genetic variability using allele frequencies, observed heterozygosity, F-statistics (FIT, FIS, FST), test for Hardy-Weinberg and Genetic distance. Eleven variants were found at the five loci studied, two co-dominant allele A and B controlling three genotypes AA, AB, and BB were observed at Haemoglobin, Carbonic Anhydrase, Albumin and Esterase1 loci for both indigenous and exotic turkey breeds, a third allele C was observed in Transferrin locus. Allele A was the most frequency at the Hb, CA, Alb and Es1 locus in Nigerian indigenous turkey with frequencies 0.541, 0.541, 0.520, and 0.520 respectively and exotic turkey at Hb, Alb, and Es1 with frequencies 0.508, 0.617, and 0.508 respectively. Chi Square result indicated deviations from Hardy Weinberg equilibrium in the two populations. The average heterozygosity values were 0.56 and 0.477 indicating high genetic variability, heterozygote excess FIT was estimated at -0.050 while within breed excess as evaluated by FIS ranged from 0.370 to -0.336. The fixation index FST revealed that genetic diversity within the studied population was slightly differentiated. Genetic distance among the populations quantified through calculation of Nei’s Genetic distance was 0.008 while the identity was 0.992. Similarity in the estimated genetic variability parameters between the breeds indicates that the populations are closely related and there were no appreciable differences among them. This result obtained may be used as an initial guide in defining objectives for further investigations of genetic diversity and developing conservation strategies.Keywords: Electrophesis; Genetic distance; Polymorphism; Structural loci

Preliminary Assessment of Within-Ecotype Genetic Diversity at the Haemoglobin Locus in the Tiv Local Chickens in Makurdi, Nigeria

This experiment was designed to assess within-ecotype genetic diversity at the haemoglobin (Hb) locus in the Tiv local chickens of Nigeria in Makurdi. Eighty-two (82) blood samples were collected from each bird using needles and vials (SARSTEDT Monovette®). Haemoglobin genotypes were determined using cellulose acetate electrophoresis. Data were analyzed using Population Genetics Simulation (PopGen.S2) software. The result revealed three haemoglobin genotypes (HbAA, HbAB and HbBB) controlled by two co-dominant haemoglobin alleles HbA and HbB in the Tiv local chicken population in Makurdi. Genotype frequencies of HbAA, HbAB and HbBB were 0.44, 0.32 and 0.24, respectively, in the entire chicken population. The gene frequencies of HbA and HbB observed in this study were 0.60 and 0.40, respectively in the entire population. There was moderate heterozygosity (0.48) at the haemoglobin locus in the local chicken population in Makurdi, which is an advantage to the local chicken population.

Biochemical characterization of the nigerian indigenous guinea fowl (Numida meleagris)

Blood protein polymorphism has been extensively used for characterization and estimation of genetic diversity in farm animals. A study on biochemical characterization and estimation of genetic diversity of Nigerian indigenous guinea fowls (Numida meleagris) was conducted using four blood proteins {Haemoglobin (Hb), Carbonic anhydrase (CA), Transferrin (Tf) and Albumin (Alb)}. Cellulose acetate electrophoresis indicated that all the protein markers were polymorphic; expressing two co-dominant genes and two genotypes at their respective locus. Heterozygouse genotypes were prevalent at Hb, Tf and Alb loci while homozygoutes were more frequent for CA. Allelic constitution was similar (A and B) for Hb, Tf and Alb while F and S were typed at CA locus. Gene A had higher frequency of occurrence at Tf and Alb loci while gene F and B was prevalent at CA and Hb locus, respectively. Average estimated genetic diversity (heterozygosity) across the genetic systems was 0.40 and moderate. Prevalence of genes F, A and B at their respective locus is suggestive of their relevancies to the survival and adaptability of the studied population to its natural habitat.

Investigation of haemoglobin polymorphism in Ogaden cattle

Background and Aim: The Ogaden cattle is one among the tropical cattle breeds (Bos indicus) widely distributed in eastern and south eastern part of Ethiopia. The breed has been evolved in arid and semi arid agro-ecological setup, but later on distributed and adapted to the wide agro-ecological zones. Because of its multi-purpose role, the Ogaden cattle have been used for milk, beef, and income generation. Information on the inherent genetic diversity is important in the design of breeding improvement programmes, making rational decisions on sustainable utilization and conservation of Animal Genetic Resources. Limited information is available about genetic variation of Ogaden breed at molecular level. The present investigation was aimed to study the biochemical polymorphism at the Hemoglobin (Hb) locus. Materials and Methods: Blood samples collected from 105 Ogaden cattle maintained at Haramaya beef farm by jugular vein puncture were subjected to agarose gel electrophoresis [pH range 8.4-8.5] to study the polymorphic activities of haemoglobin. Results: Three types of phenotypes were detected i.e. a slow moving (AA) band, fast moving (BB) band and a combination of slow + fast moving bands (AB). The frequency of the fast moving band was less [13 (12.3%)] than the slow moving band [57 A (54.2%)]. Both slow & fast moving phenotype was observed in 35 (33.3%) animals. The gene frequency of HB allele was B 0.709 and that of HB allele 0.291. 2 Conclusion: The distribution of phenotypes was in agreement with codominant single gene inheritance. The Chi-square (˜ ) test revealed that the population is under Hardy-Weinberg equilibrium.

Haemoglobin Polymorphism in Red Sokoto Goats of Nigeria.

This study describes the genetic structure from the Hb locus in goats of the Red Sokoto type. The haemotypification of the individuals at the Hb locus was achieved by Cellulose acetate electrophoresis. The haemoglobin polymorphism in the Red Sokoto goat was identified in the electrophoretic field of three migration zones: the fast haemoglobin named HbA type, the intermediate migration labelled HbAHbB type and the slow haemoglobin designated HbB type. These phenotypes were determined by the two co-dominant alleles, HbA and HbB. The two alleles control three haemoglobin genotypes: two homozygotes, HbAHbA and HbBHbB, and one heterozygote, HbAHbB. The allele HbA had a higher frequency (60.4%) than the allele HbB (39.6%). The HbAHbB heterozygotes had a higher incidence in the population (64.15%) in comparison with the other two homozygous genotypes; the HbAHbA had a middling frequency (28.30%) and HbBHbB had the least occurrence (7.55%). The observed haemoglobin homozygotness (35.8%) was less than the haemoglobin heterozygotness (64.2%) in the current study. This indicates that environmental conditions, selection system or breeding methods has disturbed the Hardy-Weinberg genetic equilibrium at the Hb locus level in the population of Red Sokoto goats.

Precision of Hunchback Expression in the Drosophila Embryo

Activation of the gap gene hunchback (hb) by the maternal Bicoid gradient is one of the most intensively studied gene regulatory interactions in animal development. Most efforts to understand this process have focused on the classical Bicoid target enhancer located immediately upstream of the P2 promoter. However, hb is also regulated by a recently identified distal shadow enhancer as well as a neglected "stripe" enhancer, which mediates expression in both central and posterior regions of cellularizing embryos. Here, we employ BAC transgenesis and quantitative imaging methods to investigate the individual contributions of these different enhancers to the dynamic hb expression pattern. These studies reveal that the stripe enhancer is crucial for establishing the definitive border of the anterior Hb expression pattern, just beyond the initial border delineated by Bicoid. Removal of this enhancer impairs dynamic expansion of hb expression and results in variable cuticular defects in the mesothorax (T2) due to abnormal patterns of segmentation gene expression. The stripe enhancer is subject to extensive regulation by gap repressors, including Kruppel, Knirps, and Hb itself. We propose that this repression helps ensure precision of the anterior Hb border in response to variations in the Bicoid gradient.

Preliminary observations on effects of haemoglobin genotype and estimate of genetic distance at the HB locus in West African dwarf and red Sokoto goats

Preliminary observations on effects of haemoglobin genotype and estimate of genetic distance at the HB locus in West African dwarf and red Sokoto goats

The unique structure of the Paramecium caudatum hemoglobin gene: The presence of one intron in the middle of the coding region

The gene encoding hemoglobin (Hb) in the ciliated protist, Paramecium caudatum, has been cloned and sequenced. A single Hb locus was detected on an isolated genomic fragment with a size of approx. 15 kbp. This gene contained 443 bp. The 5′ transcriptional regulatory region contained TATA box- and CAAT box-like sequences which resemble the structure of the promoter region in higher eukaryotic genes. The amino acid sequence deduced from the gene agreed precisely with that of the major Hb component. It was an unusual structure, much smaller than Hbs from many other organisms. Furthermore, all of the untranslated regions in this gene were also small. Particularly, one intervening sequence (intron) being only 23 bp was shorter than any other introns reported for eukaryotic genes encoding protein. The position of the intron in the P. caudatum Hb gene corresponded closely to that of the second intron which had been reported only for plant Hb genes. Possible routes for the evolution of Hb genes were discussed.

Hunchback, a gene required for segmentation of an anterior and posterior region of the Drosophila embryo

The locus hunchback (hb) is a member of the gap class of segmentation genes of Drosophila. A number of X-ray-induced deletions locate the hb locus at the chromosomal site 85A3-B1, to the right of the pink locus, which maps in the same interval. A total of 14 EMS and 3 X-ray-induced hb alleles have been studied. Homozygous mutant embryos show deletions of segments in two separate regions. In the six strong alleles, the labium and all three thoracic segments are deleted anteriorly while posteriorly the 8th abdominal segment and adjacent parts of the 7th abdominal segment are lacking. The eight weak alleles show smaller deletions both in the thoracic and posterior abdominal region. In the weakest allele only part of the mesothorax is deleted. Three hb alleles produce a homoeotic transformation: superimposed on a strong or weak deletion phenotype, head or thoracic segments are transformed into abdominal segments, respectively. This suggests that hb might also be involved in the regulation of genes in the Bithorax complex ( BX-C). Fate mapping of the normal-appearing segments in strong mutant embryos using the UV-laser beam ablation technique (Lohs-Schardin et al., 1979) shows that these segments arise from the normal blastoderm regions. The mutant phenotype can be recognized soon after the onset of gastrulation in a failure to fully extend the germ band. In 6-hr-old mutant embryos, two clusters of dead cells are observed in the thoracic and posterior abdominal region. These observations indicate region specific requirement of hb gene function. The analysis of germ line chimeras by transplantation of homozygous mutant pole cells shows that hb is already expressed during oogenesis. Homozygous mutant embryos derived from a homozygous mutant germ line have a novel phenotype. The anterior affected region is enlarged, including all three gnathal segments and the anterior three abdominal segments. In addition three abdominal segments with reversed polarity are formed between the remaining head structures and the posterior abdomen. Heterozygous mutant embryos derived from a homozygous mutant germ line develop normally, indicating that maternal gene expression is not required for normal development.

Interaction between homozygous beta (0) thalassaemia and the Swiss type of hereditary persistence of fetal haemoglobin.

The interaction between beta(0) thalassemia and an heterocellular form of hereditary persistence of fetal haemoglobin (HPFH), presumably of the Swiss type, has been studied in three generations of a family in which both traits occur. The haematological parameters and the segregation of the two characters in the family suggest that the propositus, a 52-year-old male from southern Sardinia, is homozygous for beta(0) thalassemia and carrier of the HPFH. In spite of the complete suppression of adult haemoglobin synthesis, the patient is not anaemic and shows only morphological abnormalities of the red cells associated with a moderate decrease of the erythrocyte life span. Studies of the synthesis of haemoglobin chains in vitro have revealed only a mild degree of unbalance in the propositus, with a gamma/alpha ratio of 0.67, and a very slight unbalance in a 3-year-old child heterozygous for beta thalassaemia and HPFH. Preliminary analysis of the linkage between this kind of heterocellular HPFH and the beta Hb locus has been performed, utilizing all the suitable families reported in the literature. Although positive lod scores (1.535) have been obtained at a recombination fraction of 0.20, the data available are not sufficient to conclude in favour or against the linkage between the beta Hb locus and the heterocellular type of HPFH.

Relationships between hemoglobin type and reproduction, lamb, wool and milk production and health-related traits in crossbred ewes.

Relationships among hemoglobin (Hb) types and production traits were examined in 294 crossbred ewes from North Country Cheviot, Dorset, Finnsheep and Romney rams, and Suffolk and Columbia-type ewes. Hb BB ewe lambs were youngest at first estrus, while Hb AA ewe lambs were oldest. Ewe lamb fertility was similar for Hb AB and Hb BB ewes, and both were superior to Hb AA ewes. When Finnsheep crossbreds were excluded, from which Hb BB was absent, Hb BB ewes had higher ewe lamb fertility than did Hb AB ewes. There was a minor advantage of the A over the B allele in ewe lamb prolificacy. Hb BB ewes were highest, Hb AB ewes were intermediate and Hb AA ewes were lowest for average fertility, prolificacy per ewe lambing, lambs born per ewe exposed to mating, total number of lambs weaned and total kilograms of lamb weaned. Grease wool production, staple length, fiber diameter grade, incidence of medullated fibers and incidence of cotted fleeces all were similar across Hb types. Likewise, Hb type did not affect milk production or composition. Ewes with Hb AB had the lowest incidence of footrot; Hb AA and Hb BB ewes were similar. Ewes with Hb AA had the lowest fecal parasite egg counts, while ewes with Hb AB or Hb BB were similar. Ewes with Hb AA also had the lowest incidence of mastitis, Hb BB ewes were intermediate and Hb AB ewes were highest. The combination of overdominance (as for footrot resistance), beneficial effects of the A allele on health-related traits (as for mastitis and parasite resistance) and the beneficial effect of the B allele on reproductive traits, if real, could partly explain the genetic polymorphism commonly reported at the Hb locus in sheep.

Blood group and biochemical polymorphism studies in Bos bubalus

SummaryCattle reagents were used to blood type 158 water buffalo originating from Central Romania.Out of 36 cattle blood group factors which could be identified with the available reagents only 13 were present in the buffalo.Three genotypes at the Tf locus in buffaloes were identified by starch gel electrophoresis: TfBB, Tf BC and TfCC. At the Hb locus, only one phenotype Hb A was identified in all samples showing two bands a fast and a slow one.These data indicate a certain homology between cattle and water buffalo.

Studies on the mouse hemoglobin loci.

Studies on the mouse hemoglobin loci.