Polymorphism analysis and expression patterns of the IGF1 gene in the Shitou goose

Integrated analysis of whole genome and transcriptome sequencing uncovers genetic differences between Zi goose and Xianghai flying goose

Zi goose is a famous indigenous breed originating from northeast China with high annual egg production. Xianghai flying goose is a composite breed and is bred by crosses of the wild swan goose and the Zi goose. Our previous study revealed significant differences in muscle fiber characteristics between the two populations. Here, we aimed to reveal the underlying genetic basis of the above phenotype differences through whole-genome and transcriptome analysis. A total of 20 blood samples (10 Zi geese and 10 Xianghai flying geese) were used for whole genome sequencing, and eight breast muscle tissue samples (four Zi geese and four Xianghai flying geese) were used for RNA sequencing. Using the FST and XP-EHH analysis, some highly differentiated genome regions annotated with egg production (RORB, WNT4, BMPR1B) and breast muscle development (WNT7B) between the two populations were detected. RNA-sequencing analysis revealed differentially expressed genes related to muscle development (IGF1, PAX7). Moreover, several genes were detected by both genome and transcriptome analysis, and some of them were reported to be associated with muscle growth (SLIT2, PREX1) and intramuscular fat (COL6A1). These findings will help researchers better understand the genetic basis related to egg production and muscle development in geese.

Genetic Diversity Analysis and Breeding of Geese Based on the Mitochondrial ND6 Gene

To explore the differences in body-weight traits of five goose breeds and analyze their genetic diversity and historical dynamics, we collected body-weight data statistics and used Sanger sequencing to determine the mitochondrial DNA of 100 samples of five typical goose breeds in China and abroad. The results indicated that Lion-Head, Hortobagy, and Yangzhou geese have great breeding potential for body weight. Thirteen polymorphic sites were detected in the corrected 505 bp sequence of the mitochondrial DNA (mtDNA) ND6 gene, accounting for approximately 2.57% of the total number of sites. The guanine-cytosine (GC) content (51.7%) of the whole sequence was higher than the adenine-thymine (AT) content (48.3%), showing a certain GC base preference. There were 11 haplotypes among the five breeds, including one shared haplotype. We analyzed the differences in the distribution of base mismatches among the five breeds and conducted Tajima's D and Fu's Fs neutral tests on the historical dynamics of the populations. The distribution of the mismatch difference presented an unsmooth single peak and the Tajima's D value of the neutral test was negative (D < 0) and reached a significant level, which proves that the population of the three species had expanded; the Lion-Head goose population tends to be stable. The genetic diversity of Lion-Head, Zhedong White, Yangzhou, and Taihu geese was equal to the average diversity of Chinese goose breeds. The Hortobagy goose is a foreign breed with differences in mating line breeding and hybrid advantage utilization.

Origins, timing and introgression of domestic geese revealed by whole genome data

BACKGROUND

Geese are among the most important poultry species in the world. The current generally accepted hypothesis is that the European domestic geese originated from greylag geese (Anser anser), and Chinese domestic geese have two origins, most of which originated from swan geese (Anser cygnoides), and the Yili goose originated from greylag geese. To explain the origin and demographic history of geese, we selected 14 goose breeds from Europe and China and wild populations of swan and greylag geese, and whole genome sequencing data were obtained for 74 samples.

RESULTS

Population structure analysis and phylogenetic trees showed that the wild ancestor of Chinese domestic geese, except for Yili, is the swan geese, and the wild ancestor of Chinese Yili and European domestic geese is greylag geese. Analysis of the demographic history suggests that the domestication of Chinese geese occurred ~ 3499 years ago and that of the European geese occurred ~ 7552 years ago. Furthermore, gene flow was observed between domestic geese and their wild ancestors. Analysis of introgression showed that Yili geese had been introgressed by Chinese domestic geese, and the body size of Yili geese may be influenced by introgression events of some growth-related genes, including IGF-1.

CONCLUSIONS

Our study provides evidence for the origin of geese at the genome-wide level and advances the understanding of the history of goose domestication and the traits affected by introgression events.

Transcriptome Sequencing Reveals Pathways Related to Proliferation and Differentiation of Shitou Goose Myoblasts

Chinese Shitou goose is a type of large goose with high meat yield. Understanding the genetic regulation of muscle development in Shitou goose would be beneficial to improve the meat production traits of geese. Muscle development is regulated by genes related to myoblast proliferation and differentiation. In this study, the RNA-seq method was used to construct the mRNA and lncRNA expression profiles of Shitou goose myoblasts and myotubes. A total of 1664 differentially expressed (DE) mRNAs and 244 DE-lncRNAs were identified. The alternative mRNA splicing in proliferation and differentiation stages was also analyzed. Notably, pathways enriched in DE-mRNAs, DE-splicing transcripts, and DE-lncRNAs all point to the Wnt signaling pathway, indicating that the Wnt signaling is a key regulatory pathway of muscle development in Shitou goose. We also constructed the interactive network of DE-lncRNAs and DE-mRNAs and revealed some key genes of lncRNAs regulating the proliferation and differentiation of myoblasts. These results provide new insights for the study of the muscle development of the Shitou goose.