Localisation of the genomic sequence interval for the blue eggshell gene using an F2 resource population of Dongxiang chickens.

1. In order to identify the molecular interval containing the blue shell gene (O locus), linkage analysis was conducted with three microsatellite markers, (TTA)(n), (TG)(n) and (tg)(n), and a SNP in intron 1 of SLCO1C1 (solute carrier organic anion transporter family, member 1C1; A locus) to map the O locus in an F2 resource population of Dongxiang chickens. 2. Linkage analysis based on 98 F2 hens resulted in estimation of the best map order of the O locus with other linked markers as: (TTA)(n)-(TG)(n)-A-O-(tg)(n). 3. Based on these results, we inferred that the O locus was located between the A and (tg)(n) loci, that is, Chr1:67,296,991-69,140,571, which is the first genomic sequence interval to be established for the blue eggshell gene.

Comparison of the total amount of eggshell pigments in Dongxiang brown-shelled eggs and Dongxiang blue-shelled eggs.

Based on the knowledge of the heme bio-synthetic and metabolic pathway and the structures of biliverdin and protoporphyrin, experiments were carried out to compare the difference between the total quality of eggshell pigments in blue-shelled eggs and brown-shelled eggs from the same population (Dongxiang, China) and to analyze the correlation between the quantity of protoporphyrin and biliverdin in the 2 kinds of eggshells. It was found that there was no significant difference between the total quantity of eggshell pigments in Dongxiang blue-shelled eggs and Dongxiang brown-shelled eggs (P = 0.9006), and a highly significant positive correlation between the quantity of protoporphyrin and biliverdin in blue eggshells (P < 0.01) and a significant positive correlation between the quantity of protoporphyrin and biliverdin in brown eggshells (P < 0.05). These results suggested that eggshell protoporphyrin and eggshell biliverdin probably derived from common precursor material.

Study of the deposition process of eggshell pigments using an improved dissolution method.

An improved dissolution method called layer-by-layer dissolution was adopted to study the process of eggshell deposition, which is opposite to the process of eggshell dissolution. In the present study, blue and brown eggshells from 2 Chinese indigenous chicken breeds, Dongxing and Shouguang, respectively, were analyzed with layer-by-layer dissolution. The results showed that the deposition velocity of the eggshell pigments in the top (first) eggshell layer was the highest compared with other layers, which were biliverdin and protoporphyrin in blue eggshell or primarily protoporphyrin in brown eggshell. It was also revealed that the deposition processes of biliverdin and protoporphyrin were synchronous in the blue eggshell of the Dongxiang chicken in the present study.

Expression pattern of HIF1α mRNA in brain, heart and liver tissues of Tibet chicken embryos in hypoxia revealed with quantitative real-time PCR.

The problem of hypoxia adaptation in high altitudes is an unsolved brainteaser in the field of the life sciences. As one of the best chicken breeds with adaptability to highland environment, the Tibet chicken, is genetically different from lowland chicken breeds. It is well known that hypoxia has significant impact on growth by inducing the expression of the alpha subunit of the heterodimeric transcription factor, hypoxia-inducible factor 1 (HIF1α). In the present study, HIF1α expression in brain, heart and liver tissues of the Tibet and Dwarf Recessive White chicken embryos were investigated at the different development stages of days 10, 17 and 20 by real-time PCR, and the expression pattern of HIF1α in chicken embryos of the two chicken breeds incubated under conditions of hypoxia (13% O2) and normoxia (21% O2) was studied. The incubation mortality of the Tibet chicken was lower than the Dwarf Recessive White chicken during the whole incubation in hypoxia, and the mRNA expression of HIF1α had presented the differences in three tissues. The results implied that the hypoxia adaptability of the Tibet chicken embryo was higher than the Dwarf Recessive White chicken, especially in the early stage (day 10) and at a later time (day 20) during the incubation period, but the mechanism of the oxygen transfer of embryos of mountain species is not completely understood, and hypoxia adaptability of the Tibetan chicken remains to be studied further.

East Asia review 1978-79. Singapore.

PIP: As Singapore has reached replacement level fertility as of 1975, the goals of its national family planning and population program are to maintain current population rates. This is being carried out through combined efforts of several government ministries. Despite a rise in the crude birth rate from 16.9 per 1000 in 1978 to 17.3 per 1000 in 1979, rate of natural increase has remained at 1.2%. Net reproduction rate is actually below fertility level. Program activities have been maintained, including mass campaigns in family planning in rural areas. Seminars on population education were given to school teachers through the Ministry of Education and campaigns aimed at factory workers are being jointly launched by the Singapore Family Planning and Health Board, the Ministry of Health and the National Trades Union Congress. A plateau of around 15,000-16,000 new family planning acceptors joining annually has been reached. The condom has increased in popularity as a method with a reciprocal decline in the percentages of women choosing contraceptive pills. Female sterilization rates have also fallen off. The rate of abortions has declined slightly.^ieng