The relationship between atelier fashion and grass-roots style is slowly transforming from symbiotic into parasitic. Designers are sucking street savvy trendsetters dry.

There used to be a time when the clothes that came down the runway could remain aloof from the street. The styles developed in neighborhoods far removed from Seventh Avenue, Via Montenapoleone and the Rue Faubourg Saint Honore had such a wonderful rebellious edge that no one could imagine them being incorporated into designer collections.

But now, one world could not exist without the other.

The fashion of the runway draws heat and life from the styles that are generated by urban youth, from hip-hop stars and from trash-talking nouveaux riches. The spring 2000 collection that John Galliano created for Christian Dior was inspired by singer Lauryn Hill, for instance. And while the line was severely flawed--with trousers corkscrewing around the body and leather saddlebags hanging off the hips--the fact that it owed its very existence to the haute, ethno-street style of Hill is testament to high-end fashion's neediness.

When Sean "Puffy" Combs stormed the Paris couture shows, his excursion--with his bodyguards, mountain of luggage, stylists and ego--was captured in the pages of Vogue. And if anyone for a moment thought reserving a front-row seat for Combs, the embodiment of "ghetto fabulous" style, was odd, they only had to look at the photographs of Combs surrounded by models and designers in last month's Vogue to realize that Combs--who savors his image as the black Sinatra--bridges the distance between elitist fantasy and attainable dream.

If his style is overdone, ostentatious or tacky, it is gloriously so. His diamond jewelry is not the most creatively designed but the most garishly expensive. And ultimately, that's the essence of much of the work that comes down a runway--wildly overwrought simply because it can be. Like Minnie Pearl with a price tag dangling from her Sunday-best hat, Combs hangs diamond and platinum medallions around his neck as emblems of awkward pride, clumsy braggadocio and a taste level based almost solely on dollar value.

That's a combination that the fashion industry can't do without. Not to mention, he pays retail.

It's true that inexpensive clothing lines owe a debt to high-end fashion for helping to provide the creative juice that fuels the clothing industry. Without designers Marc Jacobs, Michael Kors, Miuccia Prada and others, stores such as J. Crew and Banana Republic and Club Monaco, which recently opened in Georgetown, would not be filled with beaded sweaters, long leather skirts, three-quarter-sleeve blouses.

The translation of high-end ideas into mid-priced trends has increased to whiplash swiftness, too. Ideas don't trickle down; they splash into the mainstream in a torrential downpour. Can there be a manufacturer of bluejeans who hasn't glued on a few beads or pulled out the embroidery needles to whip up Gucci-style dungarees? Prada-style sport shoes with their rubber soles have turned up among discount footwear.

But who really needs whom in this relationship? Gucci's decorated jeans hark back to early '70s do-it-yourself rhinestone kits. Those Prada sport shoes are a hybrid of orthopedic footwear and bowling shoes.

The distinctions in quality between designer brands and mass-market brands are subtle: machine embroidery rather than handmade, a wool and acrylic blend instead of cashmere. Sometimes it's as subtle as two-ply cashmere as opposed to four. The indirect effect has been that high-end fashion has been pushed to distinguish itself by finding more luxurious fabrics, offering more ornate embroidery, slapping on more sequins, obsessing about pashmina. And then slapping a crazy price on the finished product.

Then the question becomes what makes a pair of $3,000 Gucci beaded jeans so enticing? The design of the jeans or their cost? Well, the jeans are cute and all, but cute jeans don't afford many bragging rights.

High-end fashion feeds on street style and cheap style. The most interesting ideas--cargo pants, for instance--come from the ground up. Buzz, sex appeal and cool come from a couture front row populated by Combs, not the wealthy socialite Mouna Al-Rashid. For all of the design industry's complaints about knockoffs and the watering down of ideas, it is the atelier that has helped itself most generously to preexisting ideas and that has perfected the notion of hipness by association.