The large and growing wealth gap separating white and black families is the product of stubborn barriers that disproportionately consign African Americans to less-valuable real estate and lower-paying jobs, according to a new study.

A long-term examination of the financial lives of black and white Americans revealed that African Americans typically face a subtle but persistent opportunity gap that has served to widen financial disparities remaining from a long history of overt discrimination, according to a report to be released Wednesday by Brandeis University’s Institute on Assets and Social Policy.

The report, which researchers called the most detailed look ever at the roots of the racial wealth gap, is drawn from the life experiences of nearly 1,700 working Americans between 1984 and 2009. That quarter-century was an era of significant racial progress in the country. The black middle class expanded, black college graduation rates tripled, and black elected officials moved into a broad range of public offices, including the presidency.

Despite that progress, the wealth gap between whites and blacks nearly tripled among study participants, going from $85,000 per family in 1985 to $236,500 in 2009. Overall, the median net worth of whites in the study was $265,000 in 2009, compared with $28,500 for blacks. A broader survey done by federal officials has found even larger disparities, with blacks having a nickel of wealth for every dollar of wealth owned by the median white family.

The report’s authors said black families in the study group rarely benefited from inheritances and gifts to help them make down payments on homes. The result was that black families typically bought homes eight years later than whites, giving them less time to build equity. Meanwhile, even when they were able to buy a home, the typical black family did not see that property appreciate as much as did the typical white family.

One reason, the authors said, was that blacks frequently moved into predominantly black neighborhoods, where few whites shopped for homes, limiting the sales market and depressing prices.

“The racial wealth gap is the civil rights agenda for the 21st century,” said Thomas M. Shapiro, the report’s lead author and director of the institute at Brandeis. “It is a concrete way of assessing where we are as a society when it comes to racial justice.”

Researchers found that the African Americans also received little financial benefit from marriage, while it more often it put whites in a financial position to make investments that build further wealth. “Marriage among African Americans typically combines two comparatively low-level wealth portfolios and, unlike white households, does not significantly elevate the family’s wealth,” the report said.

Similarly, because they typically live so close to the financial edge, African American families were not able to leverage much wealth creation from pay raises. Whites were able to generate more than $5 in new wealth for each new dollar of income, while blacks generated 69 cents of new wealth for each new dollar of income. Shapiro said the difference was largely because blacks had to use the new income to douse financial emergencies rather than invest it.

Other factors also limit African American wealth creation. Unemployment rates are typically double those of whites, regardless of profession or education levels, while incomes and education levels are also lower.

Still, the biggest driver of the wealth gap between whites and blacks remains homeownership. “Blacks and whites have always had unequal access to the housing market,” said Thomas J. Sugrue, a professor of sociology and history at the University of Pennsylvania.

In the years after slavery, black homeownership was limited by violent racism and discrimination. The expansion of homeownership during the New Deal era all but excluded blacks. Then, redlining limited mortgage financing in many black communities.

Blacks began to gain a real foothold in homeownership in the 1960s and 1970s. But whites and businesses often fled the neighborhoods preferred by blacks, Sugrue said.

Blacks began to make steady progress in the 1990s, and the black homeownership rate peaked at 49 percent in 2004. But blacks were more often steered into subprime and other high-cost financing. The housing crash led to a massive wave of foreclosure that hit blacks disproportionately hard. The crash and subsequent recession eliminated half of the collective wealth of black families. The black homeownership rate is now 44 percent, far below the white rate of 73 percent.

Many experts say housing is still the best way for Americans of all races to build wealth. But it is critical for families to have low-cost financing so they can have predictable housing costs going forward and build wealth over time.

“If done right and responsibly, homeownership is a very important piece of the wealth puzzle for the long term,” said Reid Cramer, director of the Asset Building Program at the New America Foundation.