1 Introduction

The color of the feathers of domestic geese is very important, as it is related to aspects such as appearance, economic benefits and practical uses. Different colors like white feathers and grey feathers can affect people’s perception of the variety and market preferences, as well as breeding methods. Feather color is not just about being good-looking. It can also help identify the gender and breed of geese and affect the efficiency and income of goose farming (Huang et al., 2014; Wang et al., 2014; Azalou et al., 2024).

The color of a goose’s feathers is mainly determined by the type and distribution of melanin. This process is not controlled by a single factor but is regulated by many genes together, and the relationship is rather complex. Genes such as KIT, EDNRB2 and TYRP1 have been confirmed to have a significant relationship with changes in feather color. They can affect the development of melanocytes, the synthesis of melanin, and how pigments deposit on feathers (McGraw et al., 2003; Kozak, 2011; Liu et al., 2025). The research techniques of genomics and transcriptomics have become increasingly advanced, and researchers have also identified more candidate genes and regulatory pathways related to feather sac development and pigmentation. These results make the molecular mechanisms behind feather color clearer. Some mechanisms are similar in different species, and some are specific (Zheng et al., 2020; Ji et al., 2021; Wang et al., 2024).

This study summarizes the current understanding of the genetic mechanism of feather color, introduces the important genes and molecular pathways related to pigmentation, and also discusses the significance of these research results in domestic goose breeding, breed selection and future research. This study mainly reviews the new progress in the research of domestic goose feather color in recent years, especially the changes from finding candidate genes to conducting functional genomic research, and hopes that these contents can provide a scientific basis for improving feather color traits and protecting germplasm resources in the future.

2 Phenotypic Diversity and Classification of Feather Color in Geese

2.1 Common color patterns in domestic goose breeds

The feathers of domestic geese come in many colors. The most common ones are pure gray and pure white. In some local varieties in China, one can also see colors that fall between the two, or new types of feather colors. The Wugangtong goose is a typical example. Its feathers are either grey or white, and its chest is also white, presenting a unique pattern of "grey base and white chest" (Banerjee, 2013; Feng et al., 2022; Yang et al., 2024). Some geese also show cinnamon-colored feathers, which may gradually change from all white to all cinnamon. Some geese also have variations in the color of their beaks and irises. Their tibial colors are relatively uniform. Adult geese are generally orange, while goslings are yellow (Gladbach et al., 2010; Hamadani and Khan, 2016; Martsev, 2020).

2.2 Geographical and breed-specific distribution

Grey feathers were the most common feature of wild ancestors, and some domestic goose breeds still retain this color to this day. White-feathered geese are more commonly found in domesticated geese, especially in breeds from China and Europe (Devrim et al., 2007; Xi et al., 2020; Wen et al., 2021). Some color changes are also related to specific gene mutations. A 14-base insertion mutation in the EDNRB2 gene was found in Chinese geese. This variation did not occur in European goose breeds, indicating significant genetic differences between China and Europe (Xi et al., 2020; Gao et al., 2023). The local breed of Wugangtong goose in China is very representative. It can be classified into different phenotypes such as gray feathers, white feathers and white breasts. Terrill and Shultz (2023) and Yang et al. (2024) believe that this indicates that the diversity of feather colors may be closely related to artificial breeding and local environmental adaptation (Figure 1). Ouyang et al. (2022) and Wen et al. (2023) discovered that the Huoyan goose from Northern China shows some special feather colors, which is closely related to its environment and species history.

2.3 Heritability and observed inheritance modes

The feather color of domestic geese is mostly determined by genetics and has relatively high heritability. Their genetic patterns generally conform to Mendelian’s laws of inheritance and are manifested as dominant or recessive (Cheng et al., 2003; Yu et al., 2019). Xi et al. (2020) found that there was a 14-base insertion mutation in the EDNRB2 gene, which was recessive for white-feathered geese, indicating that white-feathered geese are homozygous, while most grey-feathered geese are heterozygous. Yang et al. (2024) demonstrated that in Wugangtong geese, gray feathers and white feathers show codominance, while the appearance of white breasts is related to the heterozygous state of this gene. Wen et al. (2023) believe that feather color may also be related to gender. In Huoyan geese, the feather color of gosling is associated with the Z chromosome and is influenced by the TYRP1 gene. Xu et al. (2022) demonstrated that there are also differences between male and female geese in terms of melanin content and the expression of related genes. In Holdobaggy geese, the feathers on the backs of female geese are darker in color because they have higher melanin content and TYRP1 expression.

3 Molecular Mechanisms of Pigmentation in Birds

3.1 Melanin biosynthesis and key genes

Melanin is the main pigment that determines the color of domestic goose feathers, and its generation and distribution processes are regulated by many key genes. The research of Wen et al. (2021) found that the KIT gene plays an important role in the formation of white feathers and gray feathers. In Chinese domestic geese, there is an 18-base deletion mutation that is closely related to white feathers. Ren et al. (2021) and Wen et al. (2023) found that, in addition to KIT, genes such as KITLG, MITF, TYRO3, AP3B1 and TYRP1 are also involved in the synthesis of melanin and the regulation of feather color. TYRP1 has a particularly significant relationship with the feather color of goslings, and it is expressed more prominently in female goslings with darker feather colors. However, ASIP was expressed more strongly in male geese with lighter colors (Xu et al., 2022; Wen et al., 2023). Mutations in the EDNRB2 and MLANA genes have also been found to be related to feather patterns and the development of melanocytes. Mutations in EDNRB2 can cause incomplete development of melanocytes in some areas, thereby forming white patches (Yang et al., 2022; Yang et al., 2024).

3.2 Regulatory elements and non-coding RNAs

After conducting chromosome-level genomic sequencing on Hungarian white geese, researchers discovered a complex regulatory system. There are 286 miRNAs, such as miR-199-x, miR-143-y and miR-23-z, etc. These mirnas can regulate the function of fibroblasts in embryonic skin and also affect the development of feather sacs (Figure 2) (Zhou et al., 2024). It indicates that the interaction between miRNA and mRNA plays a very important role in the formation and color regulation of feathers. Sello et al. (2019) also discovered some differentially expressed genes and related regulatory pathways through transcriptome analysis. For example, the calcium signaling pathway and glyceride metabolism are closely related to the development of feather sacs and pigment deposition.

3.3 Comparative insights from other avian species

By comparing the genomes of geese and other birds with their transcriptomes, researchers have gained a deeper understanding of the regulation and evolution of feather color. The feather colors of graylag and swan geese look very similar, but their mechanisms at the molecular level are different. Yang et al. (2022) found that their feather color changes were respectively related to different mutations in the EDNRB2 and MLANA genes. Comparative studies have also discovered some families of genes related to feather sac development that exist in different birds. Some genes are conserved, while others are only found in specific species. Sello et al. (2019) found that Anser anser and Anser cygnoides also showed significant differences in the enrichment of signal pathways. The cross-species analysis by Sello et al. (2019) and Yang et al. (2022) indicates that the feather coloring mechanism of birds is complex and diverse, and the color evolution among different species may occur independently through parallel evolution.

4 Candidate Gene Studies in Goose Coloration

4.1 Early gene discovery efforts

Early research on the feather color of domestic geese focused on their appearance characteristics and genetic patterns. Feather color features such as stripes on the neck, white spots on the chest, and solid or spotted patterns basically conform to Mendel's laws of inheritance, and some features show a trend of dominant inheritance. At that time, it was not very clear exactly on which chromosome many genes were located. Some studies suggested that the white feathers of Emden goose after reaching adulthood were the result of the gradually enhanced expression of a certain gene on the sex chromosome.

4.2 Mutation and polymorphism analysis

Ren et al. (2021), Yang et al. (2022), and Wen et al. (2023) discovered through whole-genome resequencing and selective clearance analysis that key candidate genes such as KIT, EDNRB2, and TYRP1 play significant roles in the feather color changes of geese. Wen et al. (2021) found that there was an 18-base deletion mutation in the intron region of the KIT gene in Chinese domestic geese, which was highly correlated with the appearance of white feathers. Yang et al. (2024) indicates that a 14-base insertion mutation on exon 3 of the EDNRB2 gene in Wugangtong geese is considered the direct cause of the new phenotype of white chest. Yang et al. (2022) found that a fixed SNP upstream of the EDNRB2 gene is associated with the white feather characteristics of gray geese. Frameshift mutations in the MLANA gene may lead to a sex-linked dilution phenotype. Genes such as KITLG, MITF and TYRP1 are also believed to be involved in regulating feather color (Ren et al., 2021; Xu et al., 2022; Wen et al., 2023).

4.3 Functional verification techniques

Transcriptome analysis revealed that mutations in EDNRB2 and MLANA would lead to a decrease in the expression of some genes related to melanin synthesis and also affect the normal development of melanocytes. As a result, white feathers or lighter color would occur (Yang et al., 2022; 2024), protein and mRNA expression analyses also support this finding. Xu et al. (2022) found that the expression of TYRP1 was higher in female geese, while ASIP was more active in male geese, which also matched the depth of their feather color. Some tissue staining experiments, including staining specifically targeting melanin, clearly demonstrated the distribution changes of melanin in feathers, proving that these gene mutations do affect feather color (Xu et al., 2022; Yang et al., 2024).

5 Functional Genomics and Gene Editing

5.1 CRISPR/Cas applications in poultry

The CRISPR/Cas gene editing technology enables researchers to precisely manipulate and study the key genes that affect feather color (Lin, 2024). Zhou et al. (2024) indicates that although there are currently few studies on the application of this technology in domestic geese, with the continuous improvement of genome sequencing and annotation, for instance, the chromosomal genome of the Hungarian white goose has been assembled. These efforts have laid a solid foundation for future gene editing research. Genes such as KIT, EDNRB2 and TYRP1 have been confirmed to be closely related to feather color changes, providing a clear research direction for functional verification and mutation analysis using CRISPR/Cas technology (Ren et al., 2021; Wen et al., 2021; Yang et al., 2022; Wen et al., 2023; Yang et al., 2024).

5.2 Overexpression and knockdown models

Researchers found through transcriptome analysis that genes such as EDNRB2, MLANA and TYRP1 were expressed at different levels in geese with different feather colors. This indicates that their functions can be understood by regulating the expression of these genes (Xu et al., 2022; Yang et al., 2022; Wen et al., 2023; Yang et al., 2024). If the expressions of EDNRB2 and MLANA are reduced, melanocytes will decrease, thereby forming white feather patches. The higher the expression of TYRP1 is, the darker the color of the feather will be (Xu et al., 2022; Yang et al., 2022; 2024).

5.3 Challenges in applying functional genomics to geese

Compared with chickens, geese still lack mature transgenic and gene editing systems, making it difficult to verify many candidate genes in experiments (Sello et al., 2019; Zhou et al., 2024). Feather color is not determined by a single gene. Usually, multiple genes and regulatory elements act together, and the genetic structure is very complex, making it more difficult to explain in research (Ren et al., 2021; Yang et al., 2022; 2024). The gene expression patterns and signaling pathways among different goose breeds are also different, meaning that the research results from one breed may not be suitable for application to other breeds (Sello et al., 2019). There are still some practical problems. For instance, genetically modified geese can trigger ethical controversies and pose considerable technical difficulties, which have restricted the progress of research.

6 Genome-Wide and Transcriptomic Approaches

6.1 Whole genome resequencing and GWAS

Studies have identified multiple important genetic loci through population resequencing and genome-wide association studies (GWAS). Wen et al. (2021) suggested that an 18-base deletion mutation in the KIT gene has a strong relationship with the white feather characteristics of Chinese domestic geese. In the same year, Ren et al. (2021) also discovered some other candidate genes through whole-genome scans, such as KITLG, MITF and TYRO3, which may regulate the expression of feather color through selection differences between white-feathered and grey-feathered goose flocks. In Huoyan geese, selective clearance analysis revealed that TYRP1 is a potential key gene affecting the feather color of young geese, enriching the understanding of genes related to feather color (Wen et al., 2023). Yang et al. (2022) also discovered specific mutations and expression differences of EDNRB2 and MLANA in the comparative genomic study of graylag and swan geese, all of which are related to the phenotype of feather color.

6.2 RNA-seq analysis of feather follicles

The feather sacs in the embryonic skin of Anser anser and Anser cygnoides were compared, and tens of thousands of unigene and differentially expressed genes (DEGs) were identified. Sello et al. (2019) found through functional analysis that pathways such as calcium signaling pathways and glyceride metabolism pathways play a key role in feather formation, and these pathways are also species-specific. Yang et al. (2022) and Yang et al. (2024) conducted transcriptome comparisons between the white feather region and the gray feather region in the study of feather color patterns and found that genes related to melanin production, such as EDNRB2 and MLANA, were significantly downregulated in the white feather region, indicating that transcriptional regulation might be the key reason for the different colors. Xu et al. (2022) discovered gender-related gene expression differences in feather sacs. For instance, TYRP1 expression was higher in female geese, while ASIP expression was higher in male geese, which was also consistent with the differences in their feather colors.

6.3 Integration with epigenomic data

Researchers combined functional genomics in the chromosomal genomic sequencing of Hungarian white geese and discovered a regulatory network of miRNA and mRNA, which is related to the development of feather cysts, indicating that epigenetic regulation may play an important role in feather coloring (Zhou et al., 2024). If epigenetic data such as miRNA expression profiles can be combined with the existing genomic and transcriptome information, a more comprehensive understanding of the genetic mechanism and regulatory mode of feather color in domestic geese can be achieved.

7 Environmental and Hormonal Influences

7.1 Effects of light, diet, and stress

In the genomic analysis of Huoyan geese, it was found that they can adapt to the cold northern climate. This is because they have some genes related to stress response, metabolism and immunity in their bodies. Wen et al. (2023) believe that these genes may be related to feather color, indicating that environmental stress can drive genetic changes related to feather color. Although there are not many studies on how light and nutrition affect the color of goose feathers at present, in other birds, there is already a lot of evidence suggesting that these factors can regulate pigment deposition and feather quality. Wen et al. (2023) also discovered many stress-related genes in goose breeds adapted to different climates, supporting the view that environmental stress can affect feather color by regulating gene pathways.

7.2 Endocrine regulation of plumage color

Hormones related to gender have a significant impact on the feather color of geese. Xu et al. (2022) found in their study on Holdobaggy geese that the color of the feathers on the backs of female gogings is darker than that of males, which is closely related to the higher melanin content in the feather sacs and the expression differences of melanin-related genes such as TYRP1 and ASIP. Sex hormones may start to play a role during embryonic development, regulating the expression of certain key genes to cause differences in feather color between male and female geese. This regulatory mechanism may be the result of the interaction between gender-specific hormone signals and the genetic mechanism of melanin synthesis.

7.3 Gene-environment interactions

Through selective clearance analysis, researchers found that pigment-related genes such as TYRP1 and KIT, as well as genes related to environmental adaptation such as PIP5K1B and NMNAT3, were all subject to natural selection in goose flocks under different climates (Ren et al., 2021; Wen et al., 2021; 2023), indicating that the interaction between genes and the environment plays an important role in feather color formation. Researchers also identified candidate genes in the same group of geese that are related to both feather color and climate adaptation, indicating that environmental stress may directly affect the coloring genes or function through a mechanism where one gene controls multiple traits (pleiotropy). This changing relationship indicates that when studying the color of goose feathers, both genetic and environmental factors need to be taken into account in order to understand the mechanism of feather color formation more comprehensively.

8 Case Study: Genetic Basis of White vs. Gray Plumage in Wanxi White Goose

8.1 Background and phenotypic description

The Wanxi White Goose is a domestic goose breed in China. It has two main feather colors: white feathers and gray feathers. Although wild geese (generally regarded as the ancestors of domestic geese) are usually grey-feathered, both white-feathered and grey-feathered types have been retained in domestic goose populations through targeted breeding (Wen et al., 2021).

8.2 Molecular findings

In the whole-genome scans of white-feathered and grey-feathered domestic geese in this case study, it was found that 346 genes showed significant genetic differences between these two feather colors. A locus in the intron region of the KIT gene is most closely related to feather color, especially an 18-base deletion mutation, which shows a very strong correlation in white-feathered geese. Although the relationship between KIT mutations and feather color changes has been widely studied in mammals, Wen et al. (2021) was the first to confirm a clear link between the KIT gene and feather color in birds, which is of great significance to Chinese domestic geese.

8.3 Breeding and conservation implications

Confirming the key role of the KIT gene in the regulation of white and gray feathers provides important molecular evidence for domestic goose breeding. Breeders can utilize the differences in KIT loci through genetic marker-assisted selection (MAS) to selectively and retain individuals with white or gray feathers in a targeted manner, helping to improve and stabilize the feather color of goose flocks (Wen et al., 2021). Understanding the genetic basis of feather color also helps protect the genetic diversity of domestic geese and provides scientific support for the sustainable management of white-feathered and gray-feathered populations.

9 Challenges and Future Perspectives

9.1 Major bottlenecks in current research

The molecular mechanism of feather color changes is not yet fully understood. Although candidate genes such as KIT, EDNRB2 and TYRP1 have been regarded as the main influencing factors, many genes that may be involved in regulation have not been identified or have not undergone functional verification (Xu et al., 2022; Yang et al., 2022; 2024). Most current studies focus on a few varieties or groups, which limits the generalization of research results and may also miss some important genetic diversity (Ren et al., 2021; Wen et al., 2021; Wen et al., 2023). High-quality genomic assembly and multi-omics data are still relatively scarce, which also makes it difficult to establish a complete explanatory path from genetic variations to actual feather color expression (Sello et al., 2019; Zhou et al., 2024). Xu et al. (2022) and Wen et al. (2023) hold that feather color inheritance itself is very complex and may involve multiple mechanisms such as sex-linked inheritance, autosomal inheritance, and upper sex interaction. These mechanisms have not been fully clarified yet, which also brings greater difficulties to actual breeding and genetic prediction.

9.2 Breakthrough directions for the future

Sello et al. (2019) and Zhou et al. (2024) suggest that future research should focus on integrating high-resolution genomic, transcriptomic and epigenomic data to more comprehensively identify the genes and regulatory elements related to feather color. Zhou et al. (2024) proposed that as chromosomal level genomic assembly and multi-omics analysis of species like the Hungarian white goose continue to advance, researchers will have the opportunity to delve deeper into new regulatory mechanisms such as the interaction between miRNA and mRNA, and verify these findings through functional experiments. Expanding the research to more domestic goose breeds and wild relatives is helpful for discovering the genetic basis behind the changes in feather color and understanding the relationship between feather color and environmental adaptation. Comparative genomics can reveal the parallel evolution and specific mechanisms among different species (Sello et al., 2019; Ren et al., 2021; Yang et al., 2022). Yang et al. (2024) and Zhou et al. (2024) demonstrated that the specific functions of candidate genes and the molecular pathways they are involved in can be more clearly confirmed through gene editing and in vitro functional verification. Yang et al. (2024) indicates that if these genetic research achievements can be combined with actual breeding efforts, the development of molecular breeding strategies for feather color-related traits is expected to accelerate.

9.3 Integrated outlook

The research on the feather color of domestic geese is becoming increasingly in-depth with the development of sequencing technology and functional genomics. To truly break through the current research bottleneck, it is necessary to collaborate across multiple disciplines and combine large-scale genomic data, comparative analysis and experimental verification. Such research is helpful for a clearer understanding of the genetic structure of feather color traits, improving the breeding efficiency of geese, and deepening the understanding of the entire coloring mechanism of birds.

Acknowledgments

The authors appreciates the comments from Dr. Yue on the manuscript of this study and thanks to the two team members for helping to organize the literature materials.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

References

Azalou M., Assani A.S., Kpomasse C.C., Tona K., Alkoiret I.T., and Pitala W., 2024, Phenotypic and morphometric characterization of domestic geese raised in northern Benin, Poultry Science, 103(4): 103563.

https://doi.org/10.1016/j.psj.2024.103563

Banerjee S., 2013, Morphological traits of duck and geese breeds of West Bengal, India, Animal Genetic Resources, 52: 1-16.

https://doi.org/10.1017/S2078633612000451

Cheng Y.S., Rouvier R., Hu Y.H., Tai J.J.L., and Tai C., 2003, Breeding and genetics of waterfowl, World's Poultry Science Journal, 59(4):509-519.

https://doi.org/10.1079/WPS20030032

Devrim A.K., Kaya N., Guven A., and Kocer B., 2007, Genetic diversity of local geese of varying productivity and feather color in Kars, Biochemical Genetics, 45: 515-522.

https://doi.org/10.1007/s10528-007-9092-z

Feng Z., Gong H., Mabrouk I., Fu J., Li C., Liu Z., Tian X., Sun L., Guo K., Sui Y., Zhou Y., Song Y., Min C., Niu J., Yan X., Xu X., and Sun Y., 2022, Breed-specific expression mode of the Wnt signalling pathway is involved in feather follicle morphogenesis between Anser cygnoide and Anser anser, Journal of Applied Animal Research, 50: 299-306.

https://doi.org/10.1080/09712119.2022.2066676

Gao G., Zhang H., Ni J., Zhao X., Zhang K., Wang J., Kong X., and Wang Q., 2023, Insights into genetic diversity and phenotypic variations in domestic geese through comprehensive population and pan-genome analysis, Journal of Animal Science and Biotechnology, 14: 150.

Gladbach A., Gladbach D.J., Kempenaers B., and Quillfeldt P., 2010, Female-specific colouration, carotenoids and reproductive investment in a dichromatic species, the upland goose Chloephaga picta leucoptera, 64: 1779-1789.

https://doi.org/10.1007/s00265-010-0990-4

Hamadani H., and Khan A., 2016, Morphological characterization with special reference to color variations in domestic geese (Anser anser domesticus), The Indian Journal of Animal Sciences, 86(4): 445-448.

https://doi.org/10.56093/ijans.v86i4.57779

Huang J., Zhou B., He D.Q., Chen S.Y., Zhu Q., Yao Y.G., and Liu Y.P., 2014, Sequence variation of melanocortin 1 receptor (MC1R) gene and association with plumage color in domestic geese, The Journal of Poultry Science, 51: 270-274.

https://doi.org/10.2141/jpsa.0130066

Ji G., Zhang M., Liu Y., Shan Y., Tu Y., Ju X., Zou J., Shu J., Wu J., and Xie J., 2021, A gene co-expression network analysis of the candidate genes and molecular pathways associated with feather follicle traits of chicken skin, Journal of Animal Breeding and Genetics, 138(1): 122-134.

https://doi.org/10.1111/jbg.12481

Kozák J., 2011, An overview of feathers formation, moults and down production in geese, Asian-Australasian Journal of Animal Sciences, 24(6): 881-887.

https://doi.org/10.5713/ajas.2011.10325

Lin X.F., 2024, CRISPR-Cas9 gene editing for enhancing disease resistance in cattle, Animal Molecular Breeding, 14(2): 178-186.

https://doi.org/10.5376/amb.2024.14.0010

Liu Y., Weng K., Li G., Wang H., Tan Y., and He D., 2025, Genetic and metabolic mechanisms underlying webbed feet pigmentation in geese: Insights from histological, transcriptomic, and metabolomic analyses, Poultry Science, 104(8): 105233.

https://doi.org/10.1016/j.psj.2025.105233

Martsev A., 2020, Origin and exterior features analysis of geese breeds genealogical groups in Russian gene pool herd, E3S Web Conf., 203: 01025.

https://doi.org/10.1051/e3sconf/202020301025

McGraw K.J., Beebee M.D., Hill G.E., and Parker R.S., 2003, Lutein-based plumage coloration in songbirds is a consequence of selective pigment incorporation into feathers, Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 135(4): 689-696.

https://doi.org/10.1016/S1096-4959(03)00164-7

Ouyang J., Zheng S., Huang M., Tang H., Qiu X., Chen S., Wang Z., Zhou Z., Gao Y., Xiong Y., Zeng G., Huang J., He J., Ren J., Chen H., and Yan X., 2022, Chromosome-level genome and population genomics reveal evolutionary characteristics and conservation status of Chinese indigenous geese, Communications Biology, 5: 1191.

https://doi.org/10.1038/s42003-022-04125-x

Ren S., Lyu G., Irwin D., Liu X., Feng C., Luo R., Zhang J., Sun Y., Shang S., Zhang S., and Wang Z., 2021, Pooled sequencing analysis of geese (Anser cygnoides) reveals genomic variations associated with feather color, Frontiers in Genetics, 12: 650013.

https://doi.org/10.3389/fgene.2021.650013

Sello C., Liu C., Sun Y., Msuthwana P., Hu J., Sui Y., Chen S., Zhou Y., Lu H., Xu C., Sun Y., Liu J., Li S., and Yang W., 2019, De novo assembly and comparative transcriptome profiling of Anser anser and Anser cygnoides geese species’ embryonic skin feather follicles, Genes, 10(5): 351.

https://doi.org/10.3390/genes10050351

Terrill R.S., and Shultz A.J., 2023, Feather function and the evolution of birds, Biological Reviews, 98(2): 540-566.

https://doi.org/10.1111/brv.12918

Wang J., Wei W., Xing C., Wang H., Liu M., Xu J., He X., Liu Y., Guo X., and Jiang R., 2024, Transcriptome and weighted gene co-expression network analysis for feather follicle density in a Chinese indigenous breed, Animals, 14(1): 173.

https://doi.org/10.3390/ani14010173

Wang Y., Li S.M., Huang J., Chen S.Y., and Liu Y.P., 2014, Mutations of TYR and MITF genes are associated with plumage colour phenotypes in geese, Asian-Australas J. Anim. Sci., 27(6): 778-783.

https://doi.org/10.5713/ajas.2013.13702

Wen J., Shao P., Chen Y., Wang L., Lv X., Yang W., Jia Y., Jiang Z., Zhu B., and Qu L., 2021, Genomic scan revealed KIT gene underlying white/gray plumage color in Chinese domestic geese, Animal Genetics, 52(3): 356-360.

https://doi.org/10.1111/age.13050

Wen J., Yu J., Zhang L., Li H., Wang H., Gu H., Zhao X., Zhang X., Ren X., Wang G., Chen A., and Qu L., 2023, Genomic analysis reveals candidate genes underlying sex-linked eyelid coloboma, feather color traits, and climatic adaptation in Huoyan geese, Animals, 13(23): 3608.

https://doi.org/10.3390/ani13233608

Xi Y., Wang L., Liu H., Ma S., Li Y., Li L., Wang J., Han C., Bai L., Mustafa A., and He H., 2020, A 14-bp insertion in endothelin receptor B-like (EDNRB2) is associated with white plumage in Chinese geese, BMC Genomics, 21: 162.

https://doi.org/10.1186/s12864-020-6562-8

Xu X., Wang S., Feng Z., Song Y., Zhou Y., Mabrouk I., Cao H., Hu X., Li H., and Sun Y., 2022, Sex identification of feather color in geese and the expression of melanin in embryonic dorsal skin feather follicles, Animals, 12(11): 1427.

https://doi.org/10.3390/ani12111427

Yang Y., Wang H., Li G., Liu Y., Wang C., Qiu S., Wang X., Yao J., Zhu L., and He D., 2022, Using comparative genomics to detect mutations regulating plumage variations in graylag (A. anser) and swan geese (A. cygnoides), Gene, 834: 146612.

https://doi.org/10.1016/j.gene.2022.146612

Yang Y., Wang H., Liu Y., Zhai S., Liu H., and He D., 2024, A novel codominant plumage color pattern of white breast patches in WugangTong geese was controlled by EDNRB2, Poultry Science, 103(12): 104324.

https://doi.org/10.1016/j.psj.2024.104324

Yu J., Li Z., Yu N., Liu K., and Zhao H., 2019, Genetic analysis of sex-linked plumage color traits of goose, Scientia Agricultura Sinica, 52(5): 949-954.

https://doi.org/10.5713/ajas.2013.13702

Zheng X., Zhang B., Zhang Y., Zhong H., Nie R., Li J., Zhang H., and Wu C., 2020, Transcriptome analysis of feather follicles reveals candidate genes and pathways associated with pheomelanin pigmentation in chickens, Scientific Reports, 10: 12088.

https://doi.org/10.1038/s41598-020-68931-1

Zhou Y., Mabrouk I., Ma J., Liu Q., Song Y., Xue G., Li X., Wang S., Liu C., Hu J., and Sun Y., 2024, Chromosome-level genome sequencing and multi-omics of the Hungarian White Goose (Anser anser domesticus) reveals novel miRNA-mRNA regulation mechanism of waterfowl feather follicle development, Poultry Science, 103(9): 103933.

https://doi.org/10.1016/j.psj.2024.103933