Using WGCNA (weighted gene co-expression network analysis) to identify the hub genes of skin hair follicle development in fetus stage of Inner Mongolia cashmere goat

Deciphering the molecular drivers for cashmere/pashmina fiber production in goats: a comprehensive review

Cashmere, also known as pashmina, is derived from the secondary hair follicles of Cashmere/Changthangi goats. Renowned as the world's most luxurious natural fiber, it holds significant economic value in the textile industry. This comprehensive review enhances our understanding of the complex biological processes governing cashmere/pashmina fiber development and quality, enabling advancements in selective breeding and fiber enhancement strategies. The review specifically examines the molecular determinants influencing fiber development, with an emphasis on keratins (KRTs) and keratin-associated proteins (KRTAPs). It also explores the roles of key molecular pathways, including Wnt, Notch, BMP, NF-kappa B, VEGF, cAMP, PI3K-Akt, ECM, cell adhesion, Hedgehog, MAPK, Ras, JAK-STAT, TGF-β, mTOR, melanogenesis, FoxO, Hippo, and Rap1 signaling. Understanding these intricate molecular cascades provides valuable insights into the mechanisms orchestrating hair follicle growth, further advancing the biology of this coveted natural fiber. Expanding multi-omics approaches will enhance breeding precision and deepen our understanding of molecular pathways influencing cashmere production. Future research should address critical gaps, such as the impact of environmental factors, epigenetic modifications, and functional studies of genetic variants. Collaboration among breeders, researchers, and policymakers is essential for translating genomic advancements into practical applications. Such efforts can promote sustainable practices, conserve biodiversity, and ensure the long-term viability of high-quality cashmere production. Aligning genetic insights with conservation strategies will support the sustainable growth of the cashmere industry while preserving its economic and ecological value.

Unlocking the genetic secrets of Dorper sheep: insights into wool shedding and hair follicle development

Dorper sheep is popular among farming enterprises with strong adaptability, disease resistance, and roughage tolerance, and an unique characteristic of natural shedding of wool. In a large number of observations on experimental sheep farms, it was found that the wool of some sheep still had not shed after May, thus manual shearing was required. Therefore, understanding the molecular mechanisms of normal hair follicles (HFs) development is crucial to revealing the improvement of sheep wool-related traits and mammalian skin-related traits. In this study, transcriptome analysis was performed on skin tissues of adult Dorper ewes in the shedding (S) and non-shedding (N) groups in September 2019, January 2020, and March 2020, respectively. The results identified 3,278 differentially expressed transcripts (DETs) in the three comparison groups within the S group, 720 DETs in the three comparison groups within the N group, and 1,342 DETs in the three comparison groups between the S-vs-N groups. Time-series expression analysis revealed 2 unique expression patterns in HF development, namely, elevated expression in the anagen phase (A pattern) and the telogen phase (T pattern). DETs with stage-specific expression had a significant presence in processes related to the hair cycle and skin development, and several classic signaling pathways involved in sheep HF development, such as Rap1, estrogen, PI3K-Akt, and MAPK, were detected. Combined analysis of DETs, time-series expression data, and weighted gene co-expression network analysis identified core genes and their transcripts influencing HF development, such as DBI, FZD3, KRT17, ZDHHC21, TMEM79, and HOXC13. Additionally, alternative splicing analysis predicted that the isoforms XM_004004383.4 and XM_012125926.3 of ZDHHC21 might play a crucial role in sheep HF development. This study is a valuable resource for explaining the morphology of normal growth and development of sheep HFs and the genetic foundation of mammalian skin-related traits. It also offers potential insights into factors influencing human hair advancement.

Exosomes serve as a crucial mediator of epithelial-fibroblast communication during hair follicle morphogenesis in cashmere goats

The formation of dermal condensates (DCs) through fibroblasts is a pivotal event in hair follicle morphogenesis in cashmere goats, a process that intricately involves epithelial-fibroblast communication. Exosomes (Exos), as essential mediators of intercellular communication, have garnered increasing attention in recent years, yet their precise role in hair follicle morphogenesis remains largely unknown. In this study, we focused on isolating and identifying epithelial cell-derived exosomes (Epi-Exos) from Inner Mongolian cashmere goats. Our experiments demonstrated that Epi-Exos could efficiently enter fibroblasts within 12 h of co-culture. Both direct co-culture of epithelial cells with fibroblasts and co-culture with Epi-Exos alone revealed that Epi-Exos promoted fibroblast migration while inhibiting their proliferation, changes that mirror the cellular biological characteristics observed during DC formation. Furthermore, recognizing the abundance of miRNAs carried by Exos, we conducted small RNA sequencing (small RNA-seq) on Epi-Exos. This analysis identified a panel of 54 highly expressed miRNAs within the Epi-Exos, 34 of which were also found to be abundant in fetal skin tissues of Inner Mongolian cashmere goats. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that these miRNAs were significantly enriched in cellular processes and signaling pathways related to hair follicle morphogenesis. Notably, our findings offer new perspectives on the role of miRNAs in Epi-Exos regulating DC formation and hair follicle morphogenesis in cashmere goats, with significant implications for understanding hair follicle development mechanisms and potential clinical or production benefits, including improved cashmere quality and yield through targeted exosome-mediated signaling manipulation.

Weighted gene co-expression network analysis reveals genes related to growth performance in Hu sheep

Hu sheep are a unique breed in our country with great reproductive potential, the extent of whose breeding has been steadily rising in recent years. The study subjects in this experiment were 8-month-old Hu sheep (n = 112). First of all, the growth performance, slaughter performance and meat quality of their eye muscle quality were assessed, meanwhile their live weight, carcass weight, body length, body height, chest circumference, chest depth and tube circumference were respectively 33.81 ± 5.47 kg, 17.43 ± 3.21 kg, 60.36 ± 4.41 cm, 63.25 ± 3.88 cm, 72.03 ± 5.02 cm, 30.70 ± 2.32 cm and 7.36 ± 0.56 cm, with a significant difference between rams and ewes (P < 0.01). Following that, transcriptome sequencing was done, and candidate genes related to growth performance were identified using the weighted co-expression network analysis (WGCNA) approach, which was used to identified 15 modules, with the turquoise and blue modules having the strongest association with growth and slaughter performance, respectively. We discovered hub genes such as ARHGAP31, EPS8, AKT3, EPN1, PACS2, KIF1C, C12H1orf115, FSTL1, PTGFRN and IFIH1 in the gene modules connected with growth and slaughter performance. Our research identifies the hub genes associated with the growth and slaughter performance of Hu sheep, which play an important role in their muscle growth, organ and cartilage development, blood vessel development and energy metabolic pathways. Our findings might lead to the development of potentially-useful biomarkers for the selection of growth and slaughterer performance-related attributes of sheep and other livestock.

Genome-wide runs of homozygosity signatures in diverse Indian goat breeds

The present study analyzed ROH and consensus ROH regions in 102 animals of eleven diverse Indian goat (Capra hircus) breeds using whole genome sequencing. A total of 51,705 ROH and 21,271 consensus regions were identified. The mean number of ROH per animal was highest in the meat breed, Jharkhand Black (2693) and lowest in the pashmina breed, Changthangi (60). The average length of ROH (ALROH) was maximum in Kanniadu (974.11 Kb) and minimum in Tellicherry (146.98 Kb). Long ROH is typically associated with more recent inbreeding, whereas short ROH is connected to more ancient inbreeding. The overall ROH-based genomic inbreeding (FROH) was highest for Jharkhand Black (0.602) followed by Kanniadu (0.120) and Sangamneri (0.108) among all breeds. FROH of Jharkhand Black was higher than Kanniadu  up to 5 Mb ROH length category. However, in > 20 Mb ROH length category, Kanniadu (0.98)  exhibited significantly higher FROH than Jharkhand Black (0.46). This  implies that Kanniadu had higher levels of recent inbreeding than Jharkhand Black. Despite this, due to the presence of both recent and ancient inbreeding, Jharkhand Black  demonstrated higher overall FROH compared to Kanniadu. ROH patterns revealed dual purpose (meat and dairy) and pashmina breeds as less consanguineous while recent inbreeding was apparent in meat breeds. Analysis of ROH consensus regions identified selection sweeps in key genes governing intramuscular fat deposition, meat tenderisation, lean meat production and carcass weight (CDK4, ALOX15, CASP9, PRDM16, DVL1) in meat breeds; milk fat percentage and mammary gland development (POLD1, NOTCH2, ARHGAP35) in dual purpose (meat and dairy) breeds; while cold adaptation and hair follicle development (APOBEC1, DNAJC3, F2RL1, FGF9) in pashmina breed. MAPK, RAS, BMP and Wnt signaling pathways associated with hair follicle morphogenesis in Changthangi were also identified. PCA analysis based on ROH consensus regions revealed that meat breeds are more diverse than other goat breeds/populations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03921-y.

Developmental Mapping of Hair Follicles in the Embryonic Stages of Cashmere Goats Using Proteomic and Metabolomic Construction

The hair follicle (HF) is the fundamental unit for fleece and cashmere production in cashmere goats and is crucial in determining cashmere yield and quality. The mechanisms regulating HF development in cashmere goats during the embryonic period remain unclear. Growing evidence suggests that HF development involves complex developmental stages and critical events, and identifying the underlying factors can improve our understanding of HF development. In this study, samples were collected from embryonic day 75 (E75) to E125, the major HF developmental stages. The embryonic HFs of cashmere goats were subjected to proteomic and metabolomic analyses, which revealed dynamic changes in the key factors and signalling pathways controlling HF development at the protein and metabolic levels. Gene ontology and the Kyoto Encyclopaedia of Genes and Genomes were used to functionally annotate 1784 significantly differentially expressed proteins and 454 significantly differentially expressed metabolites enriched in different HF developmental stages. A joint analysis revealed that the oxytocin signalling pathway plays a sustained role in embryonic HF development by activating the MAPK and Ca2+ signalling pathways, and a related regulatory network map was constructed. This study provides a global perspective on the mechanism of HF development in cashmere goats and enriches our understanding of embryonic HF development.

Identification of Key Genes Associated with Heat Stress in Rats by Weighted Gene Co-Expression Network Analysis

Heat stress has been a big challenge for animal survival and health due to global warming. However, the molecular processes driving heat stress response were unclear. In this study, we exposed the control group rats (n = 5) at 22 °C and the other three heat stress groups (five rats in each group) at 42 °C lasting 30, 60, and 120 min, separately. We performed RNA sequencing in the adrenal glands and liver and detected the levels of hormones related to heat stress in the adrenal gland, liver, and blood tissues. Weighted gene co-expression network analysis (WGCNA) was also performed. Results showed that rectal temperature and adrenal corticosterone levels were significantly negatively related to genes in the black module, which was significantly enriched in thermogenesis and RNA metabolism. The genes in the green-yellow module were strongly positively associated with rectal temperature and dopamine, norepinephrine, epinephrine, and corticosterone levels in the adrenal glands and were enriched in transcriptional regulatory activities under stress. Finally, 17 and 13 key genes in the black and green-yellow modules were identified, respectively, and shared common patterns of changes. Methyltransferase 3 (Mettl3), poly(ADP-ribose) polymerase 2 (Parp2), and zinc finger protein 36-like 1 (Zfp36l1) occupied pivotal positions in the protein-protein interaction network and were involved in a number of heat stress-related processes. Therefore, Parp2, Mettl3, and Zfp36l1 could be considered candidate genes for heat stress regulation. Our findings shed new light on the molecular processes underpinning heat stress.

Convergent Genomic Signatures of Cashmere Traits: Evidence for Natural and Artificial Selection

Convergent evolution provides powerful opportunities to investigate the genetic basis of complex traits. The Tibetan antelope (Pantholops hodgsonii) and Siberian ibex (Capra sibirica) belong to different subfamilies in Bovidae, but both have evolved similar superfine cashmere characteristics to meet the cold temperature in plateau environments. The cashmere traits of cashmere goats underwent strong artificial selection, and some traces of domestication also remained in the genome. Hence, we investigated the convergent genomic signatures of cashmere traits between natural and artificial selection. We compared the patterns of convergent molecular evolution between Tibetan antelope and Siberian ibex by testing positively selected genes, rapidly evolving genes and convergent amino acid substitutions. In addition, we analyzed the selected genomic features of cashmere goats under artificial selection using whole-genome resequencing data, and skin transcriptome data of cashmere goats were also used to focus on the genes involved in regulating cashmere traits. We found that molecular convergent events were very rare, but natural and artificial selection genes were convergent enriched in similar functional pathways (e.g., ECM-receptor interaction, focal adhesion, PI3K-Akt signaling pathway) in a variety of gene sets. Type IV collagen family genes (COL4A2, COL4A4, COL4A5, COL6A5, COL6A6) and integrin family genes (ITGA2, ITGA4, ITGA9, ITGB8) may be important candidate genes for cashmere formation and development. Our results provide a comprehensive approach and perspective for exploring cashmere traits and offer a valuable reference for subsequent in-depth research on the molecular mechanisms regulating cashmere development and fineness.

Expression Profile of Housekeeping Genes and Tissue-Specific Genes in Multiple Tissues of Pigs

Pigs have become an ideal model system for human disease research and development and an important farm animal that provides a valuable source of nutrition. To profile the all-sided gene expression and their biological functions across multiple tissues, we conducted a comprehensive analysis of gene expression on a large scale around the side of housekeeping genes (HKGs), tissue specific genes (TSGs), and the co-expressed genes in 14 various tissues. In this study, we identified 2351 HKGs and 3018 TSGs across tissues, among which 4 HKGs (COX1, UBB, OAZ1/NPFF) exhibited low variation and high expression levels, and 31 particular TSGs (e.g., PDC, FKBP6, STAT2, and COL1A1) were exclusively expressed in several tissues, including endocrine brain, ovaries, livers, backfat, jejunum, kidneys, lungs, and longissimus dorsi muscles. We also obtained 17 modules with 230 hub genes (HUBGs) by weighted gene co-expression network analysis. On the other hand, HKGs functions were enriched in the signaling pathways of the ribosome, spliceosome, thermogenesis, oxidative phosphorylation, and nucleocytoplasmic transport, which have been highly suggested to involve in the basic biological tissue activities. While TSGs were highly enriched in the signaling pathways that were involved in specific physiological processes, such as the ovarian steroidogenesis pathway in ovaries and the renin-angiotensin system pathway in kidneys. Collectively, these stable, specifical, and co-expressed genes provided useful information for the investigation of the molecular mechanism for an understanding of the genetic and biological processes of complex traits in pigs.

Identification of key pathways and genes that regulate cashmere development in cashmere goats mediated by exogenous melatonin

The growth of secondary hair follicles in cashmere goats follows a seasonal cycle. Melatonin can regulate the cycle of cashmere growth. In this study, melatonin was implanted into live cashmere goats. After skin samples were collected, transcriptome sequencing and histological section observation were performed, and weighted gene co-expression network analysis (WGCNA) was used to identify key genes and establish an interaction network. A total of 14 co-expression modules were defined by WGCNA, and combined with previous analysis results, it was found that the blue module was related to the cycle of cashmere growth after melatonin implantation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the first initiation of exogenous melatonin-mediated cashmere development was related mainly to the signaling pathway regulating stem cell pluripotency and to the Hippo, TGF-beta and MAPK signaling pathways. Via combined differential gene expression analyses, 6 hub genes were identified: PDGFRA, WNT5A, PPP2R1A, BMPR2, BMPR1A, and SMAD1. This study provides a foundation for further research on the mechanism by which melatonin regulates cashmere growth.

Identification of the key proteins associated with different hair types in sheep and goats

Animal-derived fiber has the characteristics of being light, soft, strong, elastic and a good thermal insulator, and it is widely used in many industries and traditional products, so it plays an important role in the economy of some countries. Variations in phenotypes of wool fibers among different species and breeds are important for industry. We found that the mean fiber diameter of cashmere was significantly smaller than that of sheep wool (p < 0.01), and sheep wool was significantly smaller than goat wool (p < 0.01). Compared with traditional proteomics technology, we analyzed cashmere, guard hair, and wool by Laber-free proteomics technology and detected 159, 204, and 70 proteins, respectively. Through the sequential windowed acquisition of all theoretical fragmentations (SWATH), 41 and 54 differentially expressed proteins were successfully detected in the cashmere vs. wool group and guard hair vs. wool group. Protein‒protein interaction network analysis of differentially expressed proteins revealed many strong interactions related to KRT85, KRTAP15-1 and KRTAP3-1. The final analysis showed that the proportion of KRT85, KRTAP15-1 and KRTAP3-1 might be the key to the difference in fiber diameter and could be used as a potential molecular marker for distinguishing different fiber types.

Identification of Genes Related to Hair Follicle Cycle Development in Inner Mongolia Cashmere Goat by WGCNA

Cashmere goat from Inner Mongolia is an excellent local breed in China, and the related cashmere product is a kind of precious textile raw material with high price. Cashmere is generated from secondary hair follicles, which has obvious annual periodicity and includes three different stages: anagen, catagen, and telogen. Therefore, we investigated skin transcriptome data for 12 months using weighted gene co-expression network analysis (WGCNA) to explore essential modules, pathways, and genes responsible for the periodic growth and development of secondary hair follicles. A total of 17 co-expression modules were discovered by WGCNA, and there is a strong correlation between steelblue module and month (0.65, p = 3E−09), anagen (0.52, p = 1E−05), telogen (−0.6, p = 8E−08). Gene expression was generally high during late anagen to catagen (June to December), while expression was downregulated from telogen to early anagen (January–May), which is similar to the growth rule of hair follicle cycle. KEGG pathway enrichment analyses of the genes of steelblue module indicated that genes are mainly enriched in Cell cycle, Wnt signaling pathway, p53 signaling pathway and other important signal pathways. These genes were also significantly enriched in GO functional annotation of the cell cycle, microtubule movement, microtubule binding, tubulin binding, and so on. Ten genes (WIF1, WNT11, BAMBI, FZD10, NKD1, LEF1, CCND3, E2F3, CDC6, and CDC25A) were selected from these modules, and further identified as candidate biomarkers to regulate periodic development of hair follicles using qRT-PCR. The Wnt signaling pathway and Cell cycle play an important role in the periodic development of hair follicles. Ten genes were identified as essential functional molecules related to periodic development of hair follicle. These findings laid a foundation for understanding molecular mechanisms in biological functions such as hair follicle development and hair growth in cashmere goats.

Gene network analysis reveals candidate genes related with the hair follicle development in sheep

Background

Merino sheep are the most famous fine wool sheep in the world. They have high wool production and excellent wool quality and have attracted worldwide attention. The fleece of the Merino sheep is composed predominantly of wool fibers grown from secondary wool follicles. Therefore, it is necessary to study the development of hair follicles to understand the mechanism of wool production. The hair follicle is a complex biological system involved in a dynamic process governed by gene regulation. The hair follicle development process is very complex and poorly understood. The purpose of our research is to identify candidate genes related to hair follicle development, provide a theoretical molecular breeding basis for the cultivation of fine wool sheep, and provide a reference for the problems of hair loss and alopecia areata that affect human beings.

Results

We analyzed mRNAs data in skin tissues of 18 Merino sheep at four embryonic days (E65, E85, E105 and E135) and two postnatal days (P7 and P30). G1 to G6 represent hair follicles developmental at six stages (i.e. E65 to P30). We identified 7879 differentially expressed genes (DEGs) and 12623 novel DEGs, revealed different expression patterns of these DEGs at six stages of hair follicle development, and demonstrated their complex interactions. DEGs with stage-specific expression were significantly enriched in epidermal differentiation and development, hair follicle development and hair follicle morphogenesis and were enriched in many pathways related to hair follicle development. The key genes (LAMA5, WNT10A, KRT25, SOSTDC1, ZDHHC21, FZD1, BMP7, LRP4, TGFβ2, TMEM79, SOX10, ITGB4, KRT14, ITGA6, and GLI2) affecting hair follicle morphogenesis were identified by network analysis.

Conclusion

This study provides a new reference for the molecular basis of hair follicle development and lays a foundation for further improving sheep hair follicle breeding. Candidate genes related to hair follicular development were found, which provided a theoretical basis for molecular breeding for the culture of fine wool sheep. These results are a valuable resource for biological investigations of fleece evolution in animals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08552-2.

Identification of the susceptibility genes for COVID-19 in lung adenocarcinoma with global data and biological computation methods

Introduction

The risk of infection with COVID-19 is high in lung adenocarcinoma (LUAD) patients, and there is a dearth of studies on the molecular mechanism underlying the high susceptibility of LUAD patients to COVID-19 from the perspective of the global differential expression landscape.

Objectives

To fill the research void on the molecular mechanism underlying the high susceptibility of LUAD patients to COVID-19 from the perspective of the global differential expression landscape.

Methods

Herein, we identified genes, specifically the differentially expressed genes (DEGs), correlated with the susceptibility of LUAD patients to COVID-19. These were obtained by calculating standard mean deviation (SMD) values for 49 SARS-CoV-2-infected LUAD samples and 24 non-affected LUAD samples, as well as 3931 LUAD samples and 3027 non-cancer lung samples from 40 pooled RNA-seq and microarray datasets. Hub susceptibility genes significantly related to COVID-19 were further selected by weighted gene co-expression network analysis. Then, the hub genes were further analyzed via an examination of their clinical significance in multiple datasets, a correlation analysis of the immune cell infiltration level, and their interactions with the interactome sets of the A549 cell line.

Results

A total of 257 susceptibility genes were identified, and these genes were associated with RNA splicing, mitochondrial functions, and proteasomes. Ten genes, MEA1, MRPL24, PPIH, EBNA1BP2, MRTO4, RABEPK, TRMT112, PFDN2, PFDN6, and NDUFS3, were confirmed to be the hub susceptibility genes for COVID-19 in LUAD patients, and the hub susceptibility genes were significantly correlated with the infiltration of multiple immune cells.

Conclusion

In conclusion, the susceptibility genes for COVID-19 in LUAD patients discovered in this study may increase our understanding of the high risk of COVID-19 in LUAD patients.

Chi-miR-130b-3p regulates Inner Mongolia cashmere goat skin hair follicles in fetuses by targeting Wnt family member 10A

The development of hair follicles (HFs) is dependent on interactions between epithelial cells and dermal fibroblasts, which may play an important role in maintaining the structure of HFs during their development and maturation. Wnt family member 10 (WNT10A) is a hub gene during HF development and maturation that may regulate the proliferation of dermal fibroblasts and epithelial cells through microRNAs (miRNAs) and messenger RNAs (mRNAs) to maintain the structural stability of HFs. In the present study, we confirmed that WNT10A is the target gene of chi-miR-130b-3p by real-time quantitative PCR, western blotting, and a dual-luciferase reporter gene assay. We successfully cultured fetal epithelial cells and dermal fibroblasts using the tissue block attachment method, and Cell Counting Kit-8 (CCK8) results showed that chi-miR-130b-3p regulates epithelial cell and dermal fibroblast proliferation by targeting WNT10A.

Chi-miR-370-3p regulates hair follicle morphogenesis of Inner Mongolian cashmere goats

MicroRNAs (miRNAs), a class of 22 nucleotide (nt) noncoding RNAs, negatively regulate mRNA posttranscriptional modification in various biological processes. Morphogenesis of skin hair follicles in cashmere goats is a dynamic process involving many key signaling molecules, but the associated cellular biological mechanisms induced by these key signaling molecules have not been reported. In this study, differential expression, bioinformatics, and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed on miRNA expression profiles of Inner Mongolian cashmere goats at 45, 55, and 65 days during the fetal period, and chi-miR-370-3p was identified and investigated further. Real-time fluorescence quantification (qRT-PCR), dual luciferase reporting, and Western blotting results showed that transforming growth factor beta receptor 2 (TGF-βR2) and fibroblast growth factor receptor 2 (FGFR2) were the target genes of chi-miR-370-3p. Chi-miR-370-3p also regulated the expression of TGF-βR2 and FGFR2 at mRNA and protein levels in epithelial cells and dermal fibroblasts. DNA staining, Cell Counting Kit-8, and fluorescein-labelled Annexin V results showed that chi-miR-370-3p inhibited the proliferation of epithelial cells and fibroblasts but had no effect on apoptosis. Cell scratch test results showed that chi-miR-370-3p promoted the migration of epithelial cells and fibroblasts. Chi-miR-370-3p inhibits the proliferation of epithelial cells and fibroblasts by targeting TGF-βR2 and FGFR2, thereby improving cell migration ability and ultimately regulating the fate of epithelial cells and dermal fibroblasts to develop the placode and dermal condensate, inducing hair follicle morphogenesis.