Assignment of CPS1, OTC, CRYD2, ARG2 and ASS genes to the chicken RH map

An attempt was made to assign five genes, CPS1, OTC, ASS, CRYD2, and ARG2, to chicken chromosomes (GGA) by radiation-hybrid mapping. OTC was assigned to GGA1; ARG2 to GGA5; CPS1 to GGA7; and CRYD2 to GGA19. ASS was not, however, assigned to a specific chromosomal position

Genetic similarity and relationships of DNA fingerprints with performance and with heterosis in Japanese quail lines from two origins and under reciprocal recurrent or within-line selection for early egg production

DNA fingerprints of Japanese quail male and female pure line breeders were obtained with probes 33.6, 33.15, and R18.1 and they yielded a total of 59 scoreable bands. Bandsharing (0 < BS < 1) was calculated within and between six quail lines of two origins, and under reciprocal recurrent (AA and BB), within-line (DD and EE) or no (PP and FF) selection. Twenty one pair types were compared. BS was 0.30 higher within line than between lines. BS with the control line was smaller for reciprocal recurrent selection lines than for lines under individual selection. Bandsharing between the two reciprocal recurrent selection lines was 0.19 lower than between lines under individual selection. These results indicate that the two selection methods had different effects on the genetic constitution of the lines, in agreement with previous observations made from the analysis of biochemical polymorphisms with the same set of birds. Egg production and weight traits of pure and crossbred progeny from fingerprinted quail were obtained and compared, and a linear relationship with the measure of bandsharing was estimated. No significant regression coefficient of performance on BS was found over all progeny genetic types. Heterosis from individual matings could also be estimated under the two selection methods since the same birds were parents of both pure and crossbred performance-tested quail. The association of heterosis with the difference between BS of parents of the purebreds and BS of parents of their half-sib crossbreds was favourable and significant for early production traits in lines DD and EE, but no relationship was found in lines AA and BB. These results indicate that the high level of heterosis obtained through reciprocal recurrent selection, and the heterosis observed under within-line selection may have, partly at least, a different genetic determinism. Therefore, the relationship of heterosis with BS may also depend on the past history of selection in the lines

Evaluation of PRNP Expression Based on Genotypes and Alleles of Two Indel Loci in the Medulla Oblongata of Japanese Black and Japanese Brown Cattle

BACKGROUND: Prion protein (PrP) level plays the central role in bovine spongiform encephalopathy (BSE) susceptibility. Increasing the level of PrP decreases incubation period for this disease. Therefore, studying the expression of the cellular PrP or at least the messenger RNA might be used in selection for preventing the propagation of BSE and other prion diseases. Two insertion/deletion (indel) variations have been tentatively associated with susceptibility/resistance of cattle to classical BSE. METHODOLOGY/PRINCIPAL FINDINGS: We studied the expression of each genotype at the two indel sites in Japanese Black (JB) and Japanese Brown (JBr) cattle breeds by a standard curve method of real-time PCR. Five diplotypes subdivided into two categories were selected from each breed. The two cattle breeds were considered differently. Expression of PRNP was significantly (p<0.0001) greater in the homozygous deletion genotype at the 23-bp locus in JB breed. Compared to the homozygous genotypes, the expression of PRNP was significantly greater in the heterozygous genotype at the 12-bp locus in JB (p<0.0001) and in JBr (p = 0.0394) breeds. In addition, there was a statistical significance in the PRNP levels between the insertion and the deletion alleles of the 23-bp locus in JB (p = 0.0003) as well as in JBr (p = 0.0032). There was no significance in relation to sex, age, geographical location or due to their interactions (p>0.05). CONCLUSION: Our results suggest that the del/del genotype or at least its del allele may modulate the expression of PRNP at the 23-bp locus in the medulla oblongata of these cattle breeds

Restoration of Genetic Resources from Ehime Native Chicken via Transferred Primordial Germ Cells (PGCs)

This experiment was designed to produce chimeric chicken by transferring primordial germ cells (PGCs) of Ehime native chicken embryos to White Leghorn ones. Fertilized eggs produced by both chicken breeds were incubated until stage 12-15 of embryonic development. The donor PGCs were taken out from blood vessel of Ehime native chicken embryos and injected into blood vessel of White Leghorn ones at the same stage. After the injection, the recipient eggs were incubated until hatching. Finally, three hatchlings including one male and two females were obtained. The birds survived to sexual maturity were used for progeny test to check chimerism. Of 29 offspring obtained by progeny test, 15 chicks showed feather color which was considered to be derived from Ehime native chicken. The present results suggest that the production of chimeric chicken by means of the transfer of PGCs may be able to restore genetic resources from endangered domestic chicken or some of the wild birds

Purebred and crossbred performances from a Japanese quail line with very small body size

In this study on Japanese quail, heterosis for weight, growth rate, and fitness traits were estimated and growth curves were fitted to traits and were compared. Crossing (SR) was performed between females of a very small line (SS) which was selected for low body weight at the age of six weeks and males of a randombred population (RR) from the same origin. Heterosis for female body weight was observed at 4 and 6 weeks of age, but it was not significant for adult size in males and females. The four growth curve models of Brody, Logistic, Gompertz and Bertalanffy were compared and the Gompertz model was the most suitable. Heterosis by the Gompertz model was negative for the age at the point of inflexion and the age at the 90% body weight of the asymptote in both sexes, but it was larger for the second trait. There was no heterosis for fertility and viability from 6 weeks up to 100 days of age in the female, but it was significant for hatchability and survival rate up to 6 weeks of age. Large heterosis was found for the age at first egg, the number of eggs and the total egg weight up to 100 days of age. However, the average egg weight of SR was lighter than that of RR, showing no heterosis.Performances en race pure et en croisement d'une lignée de caille japonaise ayant une très petite taille. Dans cette étude, l’effet d’hétérosis sur le poids, la vitesse de croissance et les caractères de fitness a été évalué chez des cailles japonaises ; de même, leurs courbes de croissance ont été ajustées et comparées. Un croisement (SR) a été réalisé entre des femelles issues d’une lignée de taille très petite (SS) sélectionnée pour un faible poids corporel à l’âge de six semaines et des mâles pris au hasard dans une population (RR) de même origine. Un effet d’hétérosis a été observé sur le poids corporel des femelles à l’âge de 4 et 6 semaines ; en revanche, à l’âge adulte, l’effet sur la taille n’a été significatif ni chez les mâles ni chez les femelles. Quatre modèles de courbe de croissance ont été comparés : courbes de Brody, logistique, de Gompertz et de Bertalanffy. Le modèle de Gompertz a été le plus adéquat. L’effet d’hétérosis avec le modèle de Gompertz a été négatif dans les deux sexes sur l’âge au point d’inflexion et l’âge à 90 % du poids corporel à l’asymptote. C’est pour ce dernier critère que l’effet a été le plus important. Il n’y a eu aucun effet d’hétérosis sur la fertilité et la viabilité, de 6 semaines à 100 jours d’âge chez les femelles. En revanche, un effet significatif a été observé sur l’aptitude à la couvaison et le taux de survie jusqu’à l’âge de 6 semaines. L’effet d’hétérosis a été important sur l’âge au premier œuf, le nombre d’œufs et le poids total de l’œuf jusqu’à l’âge de 100 jours. Toutefois, le poids moyen des œufs du croisement SR a été plus faible que celui de la population RR, et n’a montré aucun effet d’hétérosis