Shell Color Research Articles

A Comparative Study of the Internal and External Quality Characteristics of Table Eggs and the Effect of Storage Periods and Layer Strain on them under Summer Conditions

Background: Eggs are a rich source of protein and a portion of food that satisfies human demands and supplies the body with amino acids, metal elements and vitamins that are beneficial for general health. This research aimed to determine the influence of storage duration and hen breed on the internal and external quality characteristics of brown- and white-shelled eggs under different domestic storage circumstances. Methods: A total of 240 eggs from the two species were randomly selected. They were stored at a humidity of 65% and temperatures of ±1°C for 0, 15 and 30 days. All eggs were cracked to determine the egg coefficient, egg weight, egg weight loss and air chamber depth. Egg-specific density, Haugh unit values, yolk color, the presence of flesh and blood spots, white weight, yolk weight, shell integrity, white weight percentage, percentage of shell weight, yolk weight ratio and yolk weight ratio. Shell thickness, density, cleanliness, surface area and weight relative to shell area. Result: The Haugh unit, specific density, air chamber depth and shell thickness were all significantly (P£0.05) affected by the length of time eggs were stored. It had a favorable influence on shell density and weight for brown and white-shell eggs, but the Huff unit values of the eggs were negatively affected the longer they were stored. This effect was more pronounced the longer the eggs were stored. Due to the difference in shell color and the extended period of storage, there was a major change in all of the components of the egg. This was caused by the storage duration.

The use of fermented feed containing black soldier fly (Hermetia illucens) and azolla sp on egg production and egg clutch in hybrid chickens

The purpose of the study is to investigate the effect of fermented feed containing black soldier fly and azolla meal on egg production and egg clutch. The research material used 20 female hybrid chickens and local feed ingredients. The research method was conducted experimentally using a Complete Randomized (RAL) with five (5) treatments and four (4) replications respectively. The feed treatments were P0 (100% feed control), P1 (90% basal feed + 5% black soldier fly + 5% azolla), P2 (85% basal feed + 5% black soldier fly + 10% azolla), P3 (85% basal feed + 10% black soldier fly + 5% azolla), P4 (80% basal feed + 10% black soldier fly + 10% azolla). The observed parameters included egg production, egg clutch, eggshell color, and thickness. The data obtained were analyzed using Analysis of Variance (ANOVA). The study found no significant effect on egg production, egg clutch, shell color, and thickness when feeding fermented black soldier fly and azolla at different levels. It was concluded that fermented feed containing 5-10% black soldier fly and 5-10% azolla did not negatively affect egg production and egg clutch in hybrid chickens.

PcASTA in Procambarus clarkii, a novel astaxanthin gene affecting shell color

The color of crayfish (Procambarus clarkii) shells not only affects their value, but also has a significant impact on individual size. Astaxanthin is a common carotenoid that has been found in many studies to have different functions, including regulating body color formation. In this study, the levels of different carotenoids were detected using high performance liquid chromatography (HPLC) and found a significant correlation between astaxanthin content and shell color. An astaxanthin gene (PcASTA) was identified from P. clarkii, and it was expressed in tissues of crayfish with dark-red shells and green shells. The highest expression levels of PcASTA were found in the hepatopancreas, followed by the muscle. The expression of PcASTA in all tissues of red shell crayfish was higher than that of green shell crayfish, indicating that PcASTA may be involved in shell color formation in crayfish. Moreover, high water temperature and feeding β-carotene can lead to an increase in tissue expression of PcASTA and astaxanthin content in crayfish shells. The findings indicate that PcASTA may affect shell color in P. clarkii by being involved in astaxanthin synthesis and transformation.

Nutritional characteristics of different types of eggs

Objective: To analyze 5 types of poultry eggs (chicken, turkey, ostrich, duck and quail) to compare their nutritional characteristics and sensory properties.
 Design/ Methodology/ Approach: A physical analysis was performed: weight of the entire egg (weight and proportion of the albumin, yolk and shell) length and width of the entire egg, shape index, shell color, and yolk color, nutritional (determination of raw fat, protein, dry matter and ashes) and in sensory adaptation (measured through hedonic testing of adaptability through the arrangement of nine points to an individualized quantity of 97). Different types of egg used: chicken, turkey, ostrich, duck and quail.
 Results: The egg containing the most amount of protein was that of the duck (13.02 ± 0.46 %), while the sample containing the lowest result was that of the ostrich (9.47 ± 0.27 %). The type of egg that contained the fattest level was the duck (10.31 ± 0.75 %); on the other hand, the type of egg that demonstrated the least amount of fat was that of the chicken egg (8.28 ± 0.39 %).
 Results/ Findings/ Conclusion: Even though some physical differences exist in all types of eggs, they are similar and there is minimal variation in terms of their nutritional value. Therefore, these different types of eggs can be applied for consumption as substitutes for chicken eggs and as an alternative source of protein.
 Limitations of the study/ Implications: Lack of previous research in regard to comparisons of the types of analyzed eggs.

Effect of Feeding Selected Strains of Conserved Breed Hens with Diets Containing Legumes on Egg Quality and Content and Activity of Lysozyme

Abstract The aim of the study was to evaluate the effect of replacing soybean meals with legume grains in diets on laying performance of hens and egg quality, with particular emphasis on egg lysozyme content. The study included 4 breeds/strains of laying hens included in the conservation programme in Poland, i.e.: Green-legged Partridge (Z-11), Yellow-legged Partridge (Ż-33), Rhode Island Red (R-11), and Leghorn (H-22). At 41–56 weeks of age, the hens of each strain were divided into two groups: I (control) − fed ad libitum with a standard diet based soybean meal, and II (experimental) − fed ad libitum with a diet that contained beans, peas and lupins instead of soybean meal. At 56 weeks of age, 32 eggs were taken at random from each group of hens and each strain, which were subjected to quality assessment. The results of the study confirm the possibility of feeding the above-mentioned hens with diets in which soybeans were replaced with 28% of faba bean, pea, and yellow lupin grains without a significant effect on laying performance, but with a change in some egg quality characteristics. In groups of hens fed a diet without soybean, a decrease in egg and albumen weight, albumen and yolk pH values, and an increase in yolk yellowness were recorded, as well as an increase in Haugh units and air cell height and shell porosity. There was a significant effect of genotype and diet and simultaneously of both factors on the content and activity of lysozyme in the thin and thick albumen. In the experimental groups, the average content and activity of lysozyme in the thin albumen decreased and in the thick albumen increased. Regardless of diet, statistically significant variation in egg internal quality and egg shell quality between hen strains was shown, as well as a correlation between the content and activity of lysozyme in eggs and shell colour.

Características físicas de ovos de galinhas domésticas caipiras da variedade Sura no Nordeste

ABSTRACT This study aimed to analyze the physical characteristics of eggs from free-range hens of the Sura variety. One hundred eggs underwent assessment of various physical parameters, namely, whole egg weight, equatorial diameter, egg height, shell color, presence of cracks via candling, air chamber height, yolk color, presence of flesh and blood spots, albumen width and length, yolk diameter, yolk weight, and shell weight. Additional analyses included determining the albumen weight (calculated by subtracting the weights of the shell and yolk from the total egg weight), percentages of egg components, shape index, and shell index. Statistical analyses were conducted using GLM SAS software (SAS Institute). The results revealed distinct physical traits; eggs from the Sura variety, regardless of size class (large or small), typically have a more rounded shape, light brown shells, and more orange yolks. These findings confirm that Sura variety eggs possess unique characteristics that could appeal to specific market niches, potentially promoting the production of these birds, supporting biodiversity, and aiding in the prevention of their extinction.

Comparison of the Spreading History of Two Introduced Cepaea Species (Gastropoda, Helicidae) in Ukraine with Remarks on Their Phenotypic Variability

Trends of the current dispersal of Cepaea nemoralis and C. hortensis in Ukraine are analysed, which are closely related to the activities of several garden centres, which export a part of the sold seedlings of ornamental and garden plants from other European countries. Using Lviv and its environs as an example, we compared the qualitative and quantitative phenotypic composition of C. nemoralis at sites where both Cepaea species or only C. nemoralis were recently introduced. On average, the former were characterised by a greater phenotypic diversity of C. nemoralis, which may be due to a greater number of founding individuals of such colonies. At the sites of the second group, hereditary traits (brown ground colour, shell with three lower bands) or phenotypes (yellow unbanded), which are less common in the study area, were more often absent. Also, a clearly pronounced predominance of any one variant of the shell colouration was more often noted there, most often pink unbanded or yellow mid-banded.

Mollusks diversity to support mangrove tourism attractions in the mangrove forest of Nusa Lembongan, Bali, Indonesia

Research on the diversity of molluscs has been carried out in the mangrove forest of Nusa Lembongan. The purpose of this study was to determine the species of mollusks that interact in the mangrove habitat, to support a scientific interpretation of the existence of mollusks in the mangrove forest of Nusa Lembongan. The research was conducted in seven mangrove forest sites, from April to June 2022 using the quadratic method. At each research site determined five sampling squares. Identification of mollusk species based on morphological characters (shape, size, shell texture and shell color). The abundance of each species was calculated based on the number of individuals per unit area (m2). The diversity of molluscs was calculated using the Shanon-Wiener diversity index. The results showed that 24 species were found in the mangrove forest of Nusa Lembongan, 19 species from the gastropod class and 5 species from the bivalves class. Several species that were quite dominant were the mangrove periwinkle Littoria scabra, with a density of 28.4 individuals/5 m2, sulcate swamp Terebralia sulcata, a density of 10.2 individuals/5m2, mud creeper Cerithidea obtusa, with a density of 7.2 individuals/5m2. The diversity of mollusks species in the mangrove area of Nusa Lembongan is included in the moderate category with a diversity index of 2.79 and an evenness index of 0.88. Based on the diversity index, it shows that the condition of mangroves in Nusa Lembongan is still relatively good or steady. The diversity of mollusks, the abundance of each species, the unique characteristics of each species, and the presence of mollusks in the substrate or mangrove vegetation are scientific interpretations and attractive attractions for eco-friendly mangrove tours.

Selection of Superior Properties of Walnut Genotypes in Ereğli-Halkapınar (Konya) and Ayrancı (Karaman) Walnut Population

This selection study was conducted to determine the walnut genotypes with superior characteristics grown from seeds in Ereğli and Halkapınar districts of Konya province and Ayrancı district of Karaman province between 2019-2022. In 2021 on the fruits taken, 8 genotypes in total, including 5 genotypes in shelled walnuts and 4 genotypes in kernels (1 genotype received high scores in both shelled and kernel walnuts) were found to be promising. In 8 genotypes selected, the shelled weight is 10.66-26.31 g, the kernel weight is 5.32-9.82 g, the kernel percentage is 37.33-57.91%, the shell thickness is between 1.06-1.90 mm, the shell color is “light” in 1 genotype, “moderate” in 4 genotypes, “dark” in 3 genotypes, kernel color is in 1 genotype “extra light”, “light” in 7 genotypes, remove of kernel from the shell was “easy” in all genotypes. Shell adhesion was “good” in all genotypes, cracking of the shell was detected “easy” in 7 genotypes, “moderate” in 1 genotype, shell texture was “smooth” in 3 genotypes, “moderate” in 4 genotypes, and “rough” in 1 genotype. Remove of kernel from the shell was determined “easy” in all genotypes. Kernel fill and healthy kernel percentage was determined as 100% in all genotypes. At the end of the research, 6 of the selected genotypes showed homogamy, 1 showed protogeny and 1 showed protandry flowering properties.

Mitf involved in shell pigmentation by activating tyrosinase-mediated melanin synthesis in Pacific oyster (Crassostrea gigas)

Pigmentation is frequently observed in the molluscan shells, whereas the molecular regulation about these shell pigments formation is not clear. The microphthalmia-associated transcription factor (Mitf) is an important transactivator in melanin synthesis in vertebrates. Here, the Mitf containing a highly conserved basic helix-loop-helixleucine zipper (bHLH-LZ) domain was identified in an economically important marine bivalve Pacific oyster Crassostrea gigas. The Mitf was found to widespread tissue distribution and the expression was higher in the marginal mantle than in the central mantle. Particularly, the expression level of Mitf was high in black shell color oysters compared with white shell oysters. After injecting siRNA, the expression of Mitf decreased significantly, and the efficiency of RNA interference reached 53%. Besides, knockdown Mitf obviously decreased expression of tyrosinase family genes and tyrosinase activity of mantles, indicating a potential regulatory relationship between Mitf and Tyr or Typs. Simultaneously, there was a sharply reduce in the number of the melanosomes in the outer fold of mantle by silencing of Mitf. Luciferase assays in cell culture further verified that Mitf was involved in transcriptional regulation of Typ-2 and Typ-3 genes through binding to their specific promoter regions. These data argue that Mitf is involved in shell pigmentation through activating tyrosinase-mediated melanin synthesis in C. gigas.

Characteristic Profile of the Hazardous, Nutritional, and Taste-Contributing Compounds during the Growth of Argopecten irradians with Different Shell Colors.

Bay scallops (Argopecten irradians; A. irradians) are shellfish with high nutritional and economic value. However, nutritional studies on A. irradians with different shell colors are limited. This study examines the hazardous, nutritional, and taste-contributing compounds during the growth of A. irradians with different shell colors. During the growth of A. irradians, the hazardous contents were below the standard limit. Changes in the nutritional and taste-contributing compounds between months were more significant than shell color. Bay scallops had more fats, total fatty acids, and taste-contributing compounds in August and more proteins, essential fatty acids, vitamin D, vitamin B12, Cu, and Zn in September and October. In October, the golden shell color strain had more proteins, essential fatty acids, vitamin D, vitamin B12, Cu, and Zn, while the purple shell color strain had more taste-contributing compounds. A. irradians had better taste in August and higher nutritional value in September and October. In October, the golden shell color strain has higher nutritional value, and the purple shell color strain has better commercial value and taste. The correlation analysis indicates that the nutritional quality of bay scallops is affected by age (months), shell color, and seawater environment.

Dominant gingers - Discovery and inheritance of a new shell polymorphism in the great pond snail Lymnaea stagnalis.

Color polymorphism is a classic study system for evolutionary genetics. One of the most color-polymorphic animal taxa is mollusks, but the investigation of the genetic basis of color determination is often hindered by their life history and the limited availability of genetic resources. Here, we report on the discovery of shell color polymorphism in a much-used model species, the great pond snail Lymnaea stagnalis. While their shell is usually beige, some individuals from a Greek population show a distinct red shell color, which we nicknamed Ginger. Moreover, we found that the inheritance fits simple, single-locus Mendelian inheritance with dominance of the Ginger allele. We also compared crucial life-history traits between Ginger and wild-type individuals, and found no differences between morphs. We conclude that the relative simplicity of this polymorphism will provide new opportunities for a deeper understanding of the genetic basis of shell color polymorphism and its evolutionary origin.

Comprehensive analysis of differentially expressed mRNA, lncRNA and miRNA, and their ceRNA networks in the regulation of shell color in the Manila clam (Ruditapes philippinarum)

The regulatory mechanism of ceRNA network plays an important role in molecular function and biological processes, however, the molecular mechanism in the shell color of Ruditapes philippinarum has not yet been reported. In this study, we performed transcriptome sequencing on the mantle of R. philippinarum with different shell colors, and screened for mRNA, miRNA, and lncRNA. A total of 61 mRNAs, 3725 lncRNAs and 90 miRNAs were obtained from all the shell color comparison groups (all mRNAs, lncRNAs and miRNAs P < 0.05), and 7 mRNAs, 8 lncRNAs, and 4 miRNAs of the porphyrin pathway and melanin pathway were screened for competitive endogenous RNA (ceRNA) network construction. The results indicate that the ceRNA network composed of mRNA and lncRNA, centered around efu-miR-101, mle-bantam-3p, egr-miR-9-5p, and sma-miR-75p, may play a crucial regulatory role in shell color formation. This study reveals for the first time the mechanism of ceRNA regulatory networks in the shell color of R. philippinarum and providing important reference data for molecular breeding of shell color in R. philippinarum.

Experimental evidence of mate choice as the driving mechanism behind negative assortative mating for shell colour in a marine snail

Abstract How colour polymorphisms are maintained in natural populations constitutes a key subject of study for evolutionary ecologists. One of the mechanisms that has been put forward to explain this phenomenon is negative frequency-dependent selection, which can be caused by different mechanisms. Among these mechanisms is mate choice, or the selection as a potential mate of the rare or dissimilar colour morph by the choosy sex of a given species. In the context of colour polymorphism, mate choice predicts the occurrence of a negative assortative mating pattern, whereby different colour morphs mate more often than expected by chance alone. However, negative assortative mating can also result from other mechanisms, making it, at best, a fallible indicator of a mate choice-driven negative frequency-dependent selection. For this reason, experimental evidence explicitly connecting such a mating pattern to mate choice is necessary to claim that a particular colour polymorphism is being maintained by negative frequency-dependent selection. Here we present experimental evidence backing this relationship for the colour polymorphic marine gastropod Littorina saxatilis from the Ría de Vigo (NW Iberian Peninsula), although how specifically these organisms choose their mates remains unclear. This calls for further experimental efforts to clarify this issue and its relationship to the maintenance of colour polymorphism in L. saxatilis.

Scientific and educational potential of the malacological collection of the State Museum of Natural History of the National Academy of Sciences of Ukraine

The importance of the malacological collection of the State Museum of Natural History of the National Academy of Sciences of Ukraine in Lviv for the history and further development of malacological research in Ukraine is considered. The scientific potential of stock malacological materials, accumulated in the museum since the second half of the 19th century and significantly supplemented during the last decades, was analyzed in temporal and geographical aspects, as well as taking into account the taxonomic diversity and intraspecific conchological variability of the molluscs of Ukraine, the presence of typical materials, etc. It was found that the main (scientific) part of the malacological collection well represents the present land and freshwater mollusc fauna of Ukraine and its western part. Not represented in the museum's malacological collection are still some species that are mainly locally distributed in Ukraine and often have small sizes, which further complicates their sampling. Among the more recent additions to the malacological collection, we can especially mention the samples related to the study of the land mollusc fauna of the steppe zone of Ukraine, which remained poorly studied until the end of the 20th and even the beginning of the 21st century, as well as to the shell color and banding polymorphism in the Eastern European populations of two introduced species, Cepaea nemoralis and C. hortensis. Among the auxiliary part of the malacological collection, a large block of materials that can be used for exhibition purposes is selected. They allow demonstrating a wide range of topics from the taxonomic and morphological diversity of molluscs of Ukraine and the world to conchological adaptations. It can be useful when studying corresponding sections of a school biology course, as well as for students of biological specialties, amateur naturalists, etc. Various forms of virtual exhibiting allow to shown the public also numerous materials of the main (scientific) part of the malacological collection, which became possible within the framework of the Educational online program “Molluscs”. This allows us to talk about the gradual transformation of the main part of the malacological collection from a classical scientific collection to a scientific and educational one with virtual access.

An hypothesis on crustacean pigmentation metabolism: l-carnitine and nuclear hormone receptors as limiting factors

Abstract Astaxanthin (Axn) is the primary pigment molecule in crustaceans associated with quality, health and growth traits, leading to increased marketing value. Axn can be contained within the protein complex crustacyanin (CRCN) to produce an array of different shell colours, or esterified with fatty acids (FA) for storage but also contributing additional red colouration. l-Carnitine (LC) has a major role in FA oxidation and mitochondrial function optimization, which could influence the proportion of Axn complexed with FA or CRCN. Peroxisome proliferator activated receptors (PPARs) have important roles in FA and Axn uptake, and stored lipid oxidation affecting Axn homeostasis and storage in lipid bodies. Whether Axn could increase PPAR signalling and carnitine palmitoyl transferase activity, leading to induction of lipid metabolism, is not known in crustaceans. Several FA have been shown to preferentially form FA Axn-esters, including saturated fatty acids (SFA) such as C16:0 and C18:0, mono-unsaturated fatty acids (MUFA) such as C16:1 and C18:1, and poly-unsaturated fatty acids (PUFA) such as C20:4, C20:5, and C20:6. We hypothesize that manipulating the dietary ratios and inclusion of LC, Axn, and specific FA may be able to further improve pigment utilization, lipid metabolism, health, and growth in crustaceans.

Transcriptome and exosome proteome analyses provide insights into the mantle exosome involved in nacre color formation of pearl oyster Pinctada fucata martensii

Color polymorphisms in molluscan shells play an important economic in the aquaculture industry. Among bivalves, shell color diversity can reflect properties such as growth rate and tolerance. In pearl oysters, the nacre color of the donor is closely related to the pearl color. Numerous genes and proteins involved in nacre color formation have been identified within the exosomes of the mantle. In this study, we analyzed the carotenoids present in the mantle of gold- and silver-lipped pearl oysters, identifying capsanthin and xanthophyll as crucial pigments contributing to coloration. Transcriptome analysis of the mantle revealed several differentially expressed genes (DEGs) involved in color formation, including ferric-chelate reductase, mantle genes, and larval shell matrix proteins. We also isolated and identified exosomes from the mantles of both gold- and silver-lipped strains of the pearl oyster Pinctada fucata martensii, revealing the extracellular transition mechanism of coloration-related proteins. From these exosomes, we obtained a total of 1223 proteins, with 126 differentially expressed proteins (DEPs) identified. These proteins include those associated with carotenoid metabolism and Fe(III) metabolism, such as apolipoproteins, scavenger receptor proteins, β,β-carotene-15,15′-dioxygenase, ferritin, and ferritin heavy chains. This study may provide a new perspective on the nacre color formation process and the pathways involved in deposition within the pearl oyster P. f. martensii.

Determination of Morphological Differences Between Düzce Province Walnut Genotypes

In this study, carried out to select walnut types from the population of seedling walnut trees in Duzce province, fruit samples were collected form 86 trees, then significant fruit properties were evaluated. According to results, 5 walnut types were selected as promising. In the selected types, fruit weights were measured as 12.08 g (81.DZC.36)-15.47 g (81.DZC.11), kernel weight as 6.09 g (81.DZC.70)-8.44 g (81.DZC.42), kernel ratio as %41.41 (81.DZC.11)-%59.01 (81.DZC.42) and shell thickness as 1.03 mm (81.DZC.42) - 2.28 mm (81.DZC.11). Shell color was determined as dark in all types, while inner color was amber in one type, other types were light amber. The selected types were in a good condition for full and sound interior ratio. Six types gave 100% full and sound inner.

Integrative proteome and metabolome analyses reveal molecular basis underlying growth and nutrient composition in the Pacific oyster, Crassostrea gigas

In order to comprehend the molecular basis of growth, nutrient composition, and color pigmentation in oysters, comparative proteome and metabolome analyses of two selectively bred oyster strains with contrasting growth rate and shell color were used in this study. A total of 289 proteins and 224 metabolites were identified differentially expressed between the two strains. We identified a series of specifically enriched functional clusters implicated in protein biosynthesis (RPL4, MRPS7, and CARS), fatty acid metabolism (ACSL5, PEX3, ACOXI, CPTIA, FABP6, and HSD17B12), energy metabolism (FH, PPP1R7, CLAM2, and RGN), cell proliferation (MYB, NFYC, DOHH, TOP2a, SMARCA5, and SMARCC2), material transport (ABCB1, ABCB8, VPS16, and VPS33a), and pigmentation (RDH7, RDH13, Retsat, COX15, and Cyp3a9). Integrated proteome and metabolome analyses indicate that fast-growing strain utilize energy-efficient mechanisms of ATP generation while promoting protein and polyunsaturated fatty acid synthesis, activating the cell cycle to increase cell proliferation and thus promoting their biomass increase. These results uncovered molecular mechanisms underlying growth regulation, nutrition quality, and pigmentation and provided candidate biomarkers for molecular breeding in oysters. SignificanceRapid growth has always been the primary breeding objective to increase the production profits of Pacific oyster (Crassostrea gigas), while favorable nutritional quality and beautiful color add commercial value. In recent years, proteomic and metabolomic techniques have been widely used in marine organisms, although these techniques are seldom utilized to study oyster growth and development. In this study, two C. gigas strains with contrasted phenotypes in growth and shell color provided an ideal model for unraveling the molecular basis of growth and nutrient composition through a comparison of the proteome and metabolome. Since proteins and metabolites are the critical undertakers and the end products of cellular regulatory processes, identifying the differentially expressed proteins and metabolites would allow for discovering biomarkers and pathways that were implicated in cell growth, proliferation, and other critical functions. This work provides valuable resources in assistance with molecular breeding of oyster strains with superior production traits of fast-growth and high-quality nutrient value.

Fine mapping of the Cepaea nemoralis shell colour and mid-banded loci using a high-density linkage map

Molluscs are a highly speciose phylum that exhibits an astonishing array of colours and patterns, yet relatively little progress has been made in identifying the underlying genes that determine phenotypic variation. One prominent example is the land snail Cepaea nemoralis for which classical genetic studies have shown that around nine loci, several physically linked and inherited together as a ‘supergene’, control the shell colour and banding polymorphism. As a first step towards identifying the genes involved, we used whole-genome resequencing of individuals from a laboratory cross to construct a high-density linkage map, and then trait mapping to identify 95% confidence intervals for the chromosomal region that contains the supergene, specifically the colour locus (C), and the unlinked mid-banded locus (U). The linkage map is made up of 215,593 markers, ordered into 22 linkage groups, with one large group making up ~27% of the genome. The C locus was mapped to a ~1.3 cM region on linkage group 11, and the U locus was mapped to a ~0.7 cM region on linkage group 15. The linkage map will serve as an important resource for further evolutionary and population genomic studies of C. nemoralis and related species, as well as the identification of candidate genes within the supergene and for the mid-banding phenotype.