Table 1 Genes in cluster 14 with known function

AMZ1

archaemetzincin 1

metalloprotease, possibly involved in tissue remodelling to form feather follicles

[141, 142]

ANKK1 (PKK2)

ankyrin repeat and kinase domain containing 1

interacts with keratin filaments

[143]

AREG

amphiregulin

epithelial growth factor

[144]

CLDN9

claudin 9

tight junction membrane protein found in all epithelia

[145]

DLX4

homeobox protein DLX4

homeobox protein that regulates epithelial-mesenchymal interactions

[146]

EDMTF4

epidermal differentiation protein starting with MTF motif 4

markers of the feather barbule and members of the epidermal differentiation complex; this has a role in integumentary development, including feather pigmentation

[147,148,149]

EDMTFH

epidermal differentiation protein starting with MTF and rich in histidine

FK21

feather keratin 21

feather keratins

FK27

feather keratin 27

PNPLA4

patatin-like phospholipase domain-containing protein 4

enzyme with a role in retinol metabolism (retinol and related compounds regulate epithelial cell growth and differentiation)

[150, 151]

RAB38

Ras-related protein RAB38

GTPase involved in melanosome biogenesis and epithelial pigmentation

[152, 153]

RASSF10

Ras association domain family member 10

tumour suppressor that mediates the epithelial-mesenchymal transition

[154]

SDR16C5 (RDH-E2)

epidermal retinol dehydrogenase 2

overexpressed in psoriatic human skin

[155]

XG

Xg blood group

blood group antigen

[156]