Chromosome Analysis of Chicken and Quail

Chromosome Analysis of Chicken and Quail Chicken, quail and Chicken-Quail hybrids were used as objects of study, in order to investigate the crossing incompatibility between Chicken-Quail in the level of chromosome. Chromosome specimens are prepared by the peripheral blood lymphocyte cultivation, airing and embryonic, with karyotype, G and C band analysis. The results showed that the number of chromosomes of chicken and quail are 2n = 78, including 10 pairs macrochromosomesand 29 minute chromosome, but apparented differences are existed in the morphous of chromosomes, there are comparatively large difference between the number of fringe and the width of fringe of G band stripe of chicken and quail. It can be divided into 32 zones, with 155 straps and 71 positive bands for chickens. And it can be divided into 28 zones, with 138 straps and 61 positive bands for quails. Through the analysis of C zonation, it indicated that W chromosome of fission phase in all the female always show C-band and the whole band anachromasis, easil y identified, which further confirmed the C-band analysis is an effective way of birds sexing. Key words: Chicken, Quail, Hybrid Species, Karyotype According to the statistics, 56 percent of kinds of birds can be used to species hybridization and 44 percent of kinds birds can be used to intergeneric cross, epecially between family or subfamily[1]. These phenomenon of distance hybridization can make breeding materials richer and provide superordinary goods group, however, the problems accompanied by distant hybridization are cross incompatibility (hybridized combination can not obtain the offspring), and hybrid sterility. There are same matters between the crossing of chickens and quails, such as the early death of female individuals of hybrid species, only the maleness ones survivaled but there are no activity of genitical gland of hybrid species. Now the mechanism of distance cross-incompatibility of birds are imperfect, and there are no detailed cellule genetics research of generic cross. Chickens, quails and intergeneric hybrid species were used as object in this study, Chromosome specimens are prepared by the peripheral bloo d lymphocyte cultivation, airing and embryonic, with karyotype. With the comparison among the objects, G-band and C band, many valuable references for cross incompatibility and the hybrid sterility are provided between chicken and quail. Test materials Test animal Gallus gallus domestica tested 20 (10 à ¢Ã¢â€ž ¢Ã¢â‚¬Å¡, 10 à ¢Ã¢â€ž ¢Ã¢â€š ¬), quail 20 (10 à ¢Ã¢â€ž ¢Ã¢â‚¬Å¡, 10 à ¢Ã¢â€ž ¢Ã¢â€š ¬), the ripe Chicken-Quail hybrids 20 and Chicken-Quail hybrids embryos 90 adopted artificial insemination method by hybridization of chicken (à ¢Ã¢â€ž ¢Ã¢â‚¬Å¡) and quail (à ¢Ã¢â€ž ¢Ã¢â€š ¬), were taken from experimental station Animal Science and Technology Institute of Shihezi University. Reagent RPMI1640 (GIBCO); Heparin (Hua Mei biological engineering company); colchicine (BIB subpackage); Giemsa powder (Sigma subpackage); calf serum (Hua Mei biological engineering company), inactivated , cryopreservation; PHA (Institute of Pharmaceutical Industry in Guangzhou). Preparation of conventional chromosome specimen Chromosome specimens slice of chicken, quail and ripe Chicken-Quail hybrids prepared[2] by the peripheral blood lymphocyte cultivation, airing. Chromosome specimens slice of Chicken-Quail hybrids prepared by embryonic. Referring the methods of preparing the chromosome sample of G-zonation of Chen guo-hong[3] and so on(2003), then preparing the chromosome sample of C-zonation for using the regulation of BSG[4]. Chromosome analysis method Chromosome sections with Giemsa stained can be counted under a microscope. The diploid chromosome number are counted under the microscope with selecting of good chromosome spread and fission phasing of limpid appearance (50 male and 50 female). The 3 metakinesis phasing and good chromosome spread and limpid appearance selected in each poultry were carried out microphotograph under the immersion objective choice. The long and short arms of first 10 pairs chromosomes were measured by Photoshop image-processing software, then according to the following formula, calculated the relative length of each chromosomes, arm ratio and Centromere index. According to the standards of Leven, regular karyogram were got for the size, the location of centromere of chromosomes. For using the mean value of karyotype parameter, we can draw a ideograph of karyotype. Relative length=-100 Arm ratio= Centromere index=-100 The good metaphase G-band ideograph for division of zone of chicken, quail and a hybrid were shooted. With the survey of microscope, the number of stripe, the relative location of stripe, the shade of colouration and the width of stripe were all sure. The number of stripe for the first 10 pairs chromosomes of each cellule were calculated, and counted the frequency of modal number of stripe. Partited[5] the zone for referencing the pattern of the G-zonation of Gallus gallus domestica, then drawed the mode of the G-zonation of intermediate stage for chicken, quails and hybrid species. The condition of metaphase phasing C zonation with alkali treatment was observed under the microscope, selecting complete limpid metakinesis phasing of good disposal, chromatosis and disintegration for micrograph, magnification, cutting out, paring, with the analysis of the C-band characteristics, location show, and other laws, focusing on observation of the W chromosome morphous and banding circumstances . Results and analysis Karyotype analysis of Chicken, Quail and Their Hybrids Diploid (2n) cell chromosome number Chromosome sections of Chicken, quail and a hybrid were carried out conventional Giemsa staining with the selection of 100 good desintegrate phasing respectively for micrograph and the statistics of diploid chromosomes, the results shown in Table 1. Table 1 The diploid chromosomes of Chicken, Quail and Their Hybrids From table 2, 10 pairs macrochromosome and 29 pairs minute chromosome are included in the chromosomes of chickens and quails, and minute chromosome are telocentric chromosome with sex determination style of ZZ (à ¢Ã¢â€ž ¢Ã¢â‚¬Å¡) and ZW (à ¢Ã¢â€ž ¢Ã¢â€š ¬). No. 3, No. 5, No. 7, No. 9 chromosome in chicken autosome are t-type, No. 1, No. 2, No. 8 chromosome are m-type; No. 4, No. 6 chromosome are sm-type; except the quail autosome No. 1 chromosome for sm-type, No. 2 chromosome for the m-type, No. 4 chromosome for st-type; other chromosomes are t-type. The Z chromosome of chicken and quails are m-type and the fifth macrochromosome; for chicken, the W chromosome is m-type, with the length the same as No. 8 chromosome; for quail, the W chromosome is t-type, with the length between No. 7 chromosome and No. 8 chromosome. Chromosome karyotype of Chicken-Quail hybrids Table 3 The parameter of macrochromosomes of Chicken-Quail hybridsà ¯Ã‚ ¼Ã‹â€ Ã‚ ±SEà ¯Ã‚ ¼Ã¢â‚¬ ° The chromosome parameters of Chicken-Quail hybrids in Table 3, compared with chromosome karyotype parameters of chicken, quail in Table 2 found that each chromosome of every chromosome of the hybrid is basically same chromosome karyotype of chicken, quail with sex determination style for ZZ (à ¢Ã¢â€ž ¢Ã¢â‚¬Å¡) and ZW (à ¢Ã¢â€ž ¢Ã¢â€š ¬). Based on the result of Table 2 and Table 3, the ideograph of first 10 pairs of chickens, quails and hybrid species were drawed(see figure 5 and 6) , and reviewed the appearance of each chromosomes. The karyogram of chickens, quails, adult hybrid and majority hybrid species and their embryo were showed from figure 2 to figure 5. The matched-pairs of chromosomes in figure 3 and figure 4, in which the left of paired chromosomes is from chicken and the right is from quails. Disposition of Chicken-Quail hybrids early embryo sex proportion According to the chromosome karyotype and heterosome differences combing with the C-band banding pattern figure, the early sexuality identification of crossing progeny is carried out for 5 selected time. 90 embryos at early age are choosen, of which 24 female and 66 male are included. With the comparison of the theoretical, female and male ratio take on a significant difference (P