International Journal of Molecular Zoology, 2025, Vol.15, No.2, 69-77 http://animalscipublisher.com/index.php/ijmz 70 documents, it will help to more comprehensively reveal the evolutionary process of domestic geese and their global spread history. 2 The Origin of Geese 2.1 Wild ancestors: identification and distribution of gray geese and wild geese Domestic geese have two main wild ancestors, namely the gray goose (Anser anser) and the wild goose (Anser cygnoides). The grey goose first lived in Europe and West Asia, often staying in wetlands, lakes and river valleys. Wild geese are mainly active in East Asia, especially in China and Mongolia, and like to stay in wide rivers and swamps (Pingel, 2011). These two kinds of birds are different in appearance and living habits: the gray goose is larger in size and has a wider distribution area. The necks of wild geese are thinner and their range of movement is wider (Kozak, 2019; Jing et al., 2022; Wen et al., 2022). Domestication enabled these two wild ancestors to develop many different species. The domestic geese in Europe evolved from the gray goose (Anser anser), while most of the domestic geese in China (except for the Yili goose) originated from the wild goose (Anser cygnoides) (Shi et al., 2006; Kozak, 2019). Although the Yili goose is a Chinese breed, genetically it is more similar to the gray goose. This indicates that different goose flocks have a complex history during the domestication process, and there is also genetic exchange among them (Li et al., 2011; Jing et al., 2022; Wen et al., 2022). 2.2 Archaeological and genetic evidence regarding the time and place of origin Archaeological discoveries show that the process of domesticating geese in Europe and China was carried out separately. In China, goose bones unearthed from places like Tianluo Mountain in the lower reaches of the Yangtze River can prove that people began raising geese as early as over 7,000 years ago. It is estimated that geese were domesticated in Europe approximately 7 500 years ago (Jing et al., 2022; Wen et al., 2022). These early domestication situations coincided with the emergence of settled agricultural societies. In settled agricultural societies, geese were highly valued because they could provide meat, eggs and feathers (Pingel, 2011). Genetic research (including whole genome sequencing and mitochondrial DNA analysis) has confirmed that these archaeological discoveries are correct. Through the analysis of population structure and phylogeny, it can be known that domestic geese in China (except Yili geese) are descendants of wild geese, while domestic geese and Yili geese in Europe are descendants of gray geese (Shi et al., 2006; Li et al., 2011). Genomic data also show that there have always been situations of gene flow and gene penetration between wild goose populations and domestic goose populations, as well as among different domestic goose breeds, which makes the domestication of geese more complicated (Jing et al., 2022; Wen et al., 2022; Gao et al., 2023). 2.3 The debate over the singularity and diversity of domestication centers There have always been different opinions on whether there is one or multiple domestication centers for geese. Early morphological and genetic studies revealed that domestic geese have two origins: in Europe, people domesticated geese solely from gray geese (Anser anser); In China, geese were domesticated separately from the wild goose (Anser cygnoides) (Shi et al., 2006; Li et al., 2011). Recent genomic evidence strongly supports this theory of dual origin - there are significant genetic differences between European domestic geese, Chinese domestic geese and their respective wild ancestors (Jing et al., 2022; Wen et al., 2022; Gao et al., 2023). However, there are indeed breeds like the Yili goose - although it is a Chinese breed, it has a genetic connection with the grey goose, and there is evidence that some Chinese goose breeds have the same haplotype as those in Europe. This indicates that the domestication process of geese is not completely independent (Shi et al., 2006). The persistent phenomena of gene flow, hybridization and gene penetration have blurred the boundaries between different flocks of geese. This indicates that although there are at least two major domestication centers, after that, the mutual influence between them has led to the complex genetic status of domestic geese (Li et al., 2011; Jing et al., 2022; Wen et al., 2022; Gao et al., 2023).
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