Figure 1.

Cashmere growth cycle. (A) Schematic diagram showing the cashmere growth cycle, duration of daylight and sampling regimes. The HF from the Inner Mongolian Cashmere goat undergoes circannual changes, including transitions among the anagen phase (May–December), catagen phase (January) and telogen phase (February–April). The SD group was subjected to seven hours of daylight from 9:30–16:30 daily (17 h darkness: 7 h light; 17D: 7 L) from May 1^st to October 1^st (five months). The colored fonts indicate the sampling time points. At each time point, the skin from 12 goats was sampled, and RNA from six goats was isolated for RNA-seq. (B–F) Comparison of the HF structure among stages of the hair growth cycle and between the test and control groups in June. (B) June (early anagen): The HF activity is very low, and the natural photoperiod group is still in early anagen, with an incomplete HF structure. (C) The skin sections from the short-photoperiod goats indicate entry into anagen in early June (Jun_SD), with visible inner root sheaths, dense HFs and developed sebaceous glands. (D) August (anagen): Skin sections show visible inner root sheaths, dense HFs and developed sebaceous glands. (E) January (catagen): Sections show dermal papilla condensation. (F) April (telogen): HF structure is incomplete and undergoes apoptosis. SG, sebaceous gland; IRS, inner root sheath; HS, hair shaft; DP, dermal papilla. Scale bars indicate 100 μm.