The Education and Justice departments are investigating whether Yale University discriminates against Asian American applicants. (Stan Godlewski/For The Washington Post)

The Education and Justice departments are investigating whether Yale University discriminates against Asian American applicants, expanding a probe of admissions practices to a second elite university.

Yale denied the allegations Wednesday, saying it would cooperate with the investigation and defended its work to build a diverse class of students.

The joint investigation was disclosed Wednesday in a letter from the Education Department’s Office for Civil Rights to the Asian American Coalition for Education, which has challenged elite university admission practices. The coalition asserts that universities work to limit the number of Asian Americans admitted each year.

The civil rights office also said it is declining to pursue similar complaints against Dartmouth College and Brown University, citing insufficient evidence.

The action follows a Justice Department investigation of Harvard University and is fresh evidence the Trump administration is casting a skeptical eye on the affirmative action and admissions policies of elite universities. The Justice Department opened its investigation of Yale in April, the letter disclosed.

Affirmative action is generally seen as boosting racial minorities, so challenges such as this are unusual. In this case, the question is whether universities see the need to limit the number of Asian Americans admitted to ensure diversity.

The letter sent Wednesday says the Office of Civil Rights relied in part on information related to an Asian American student’s experience in applying to Yale but gave no details.

It said it would investigate “whether the University discriminated against the Applicant and other Asian American applicants by treating applicants differently based on race during the admission process.”

The agency said there was not sufficient detail to open investigations into Brown and Dartmouth. One key factor appeared to be that, unlike Yale, no applicant was alleging discrimination at those schools.

“The Department of Justice takes extremely seriously any potential violation of an individual’s constitutional rights,” department spokeswoman Kelly Laco said. An Education Department spokeswoman declined to comment.

In a letter to the university community sent Wednesday, Yale President Peter Salovey stated “unequivocally” that Yale does not discriminate in admissions against Asian Americans or other racial or ethnic groups.

He said admissions decisions are based on more than standardized testing and high school grades and include factors such as interests, demonstrated leadership and background.

“We look at the whole person when selecting whom to admit among the many thousands of highly qualified applicants,” he wrote. He said this approach complies with the Supreme Court guidelines.

Salovey offered statistics to demonstrate diversity at the school and said the portion of Asian American students has risen from 14 percent of the incoming first-year class 15 years ago to 21.7 percent for the class that just arrived.

Yale, he said, will “vigorously defend our ability to create a diverse and excellent academic community.”

Yale and other universities are subject to civil rights probes because they receive funding from the Education Department. Title VI of the Civil Rights Act prohibits discrimination on the basis of race, color or national origin. The complaints against Yale, Dartmouth and Brown were filed two years ago.

The Justice Department already has an investigation underway of Harvard University and filed a brief last month in support of a lawsuit against the school.

The Justice Department said Harvard engages in “racial balancing” in selecting its incoming class, a potential violation of affirmative action guidelines set by the Supreme Court.

Harvard has repeatedly denied the claims.

The Trump administration is approaching affirmative action much differently than the administration of President Barack Obama, whose administration argued in favor of certain programs.

In July, Trump officials rescinded Obama-era guidance offering educators a road map for legal uses of affirmative action. In its place, it signaled a preference for “race-neutral” methods of placing students.

The Harvard case could offer the Supreme Court a fresh opportunity to revisit its rules governing affirmative action. In 2016, the high court affirmed that schools may take race into account as one factor among many in pursuit of assembling a diverse class, but it put limits on the practice. For instance, it prohibited racial quotas and said schools should consider whether they can achieve their goals through race-neutral alternatives.