– Opening a Prada show can transform a mere model into a supermodel, acting as a gateway to casting in other major shows, glossy magazine covers and lucrative advertising campaigns. For more than 20 years, it has also been a white-women-only privilege.

But that changed in February when Anok Yai, 19, a Sudanese model raised in the United States after arriving from Egypt as a refugee in 2000, became the first black model to open a Prada runway show since Naomi Campbell in 1997. Joining her was Adut Akech, a South Sudanese immigrant to Australia who appeared in over 30 shows this season after making her runway debut in September when she closed the Saint Laurent show at the age of 17.

“I feel like I am part of a great moment, something quite amazing that is happening both in and outside the fashion world,” Akech said. “There has been a big increase in the number of really dark-skinned girls being cast, even from last season.”

Diversity on the catwalks (or the lack of it) is under more scrutiny than ever. While broader representations of beauty have appeared on the runways in New York, London, Paris and Milan in recent years, accusations of racism and colorism remain. But now, following in the footsteps of Alek Wek, one of the first African models to be embraced by fashion, more than two decades ago, many young women with dark skin and natural, largely chemically untreated hair have become sought-after runway models.

Aside from Yai and Akech, for example, there was Grace Bol (originally of South Sudan), who walked in Thom Browne, Givenchy and Balmain, among others; Akiima (also of South Sudanese origin), who was cast by Marc Jacobs, Jacquemus, Loewe and others; and Shanelle Nyasiase (of Kenya), who appeared at Versace, Alexander McQueen and Valentino.

“When I was younger, I always felt insecure about my looks when I looked at fashion and movie stars,” Yai said. “Although there were black women, I never saw any that had skin like me, so I always felt unattractive, like a real outsider. But I am feeling so much more optimistic now, especially when I look backstage or on runways at fashion week. There are so many more girls who look just like me.”

Edward Enninful, editor-in-chief of British Vogue and a long-standing campaigner for greater diversity in fashion, agreed. “There’s such an incredible variety of black skin tones — and it’s nice to see that full spectrum being represented,” he said.

Laura Brown, editor-in-chief of InStyle, said, “The shows finally feel rooted in the present, and frankly it is about time.”

Indeed, for the first time it was the shows that did not feature a rainbow of skin tones that stood out as problematic anomalies.

Tiya Miles, a professor of American culture and history at the University of Michigan, believes that Hollywood, fashion and beauty businesses are responding to the popular public movements demanding change in the wider global political and economic landscape.

“In reaction to a sharpening sense of white nationalist identity across America and Europe, there is a growing consciousness of the importance of visibility and vocality for people of color, particularly black people,” Miles said. “It is no coincidence that this runway model trend and movies like ‘Black Panther’ have arrived at the same time.”

The response to Yai’s Prada appearance was quick: Within three weeks of appearing on the runway she had become a viral Instagram sensation. “I thought there might be some reaction, but I never thought it would be this big,” said Yai, who was first discovered by a photographer at a Howard University homecoming celebration in October. “But as a black woman of dark skin, I feel so proud of myself.”

Akech now has 70,000 followers. Both women, bursting with excitement, are in the process of securing campaigns with major fashion brands, though they declined to specify which ones.

Still, while there are certainly more dark-skinned faces on the runways, they remain the minority. A report by Flare, a Canadian fashion magazine, found that the most racially diverse shows of the past season were in New York, where nonwhite models made up 37 percent of those on the runways. London Fashion Week was next, with 35 percent. In Milan 24 percent were nonwhite, and in Paris the figure was 26 percent.