AUSTIN -- A state Senate committee today approved, on a party-line vote, a congressional redistricting map that would increase Republican representation from Texas in the U.S. House.

The map approved 4-3 by the Senate Jurisprudence Committee would create 22 districts with Republican voting histories and 10 with Democratic histories, and probably would result in the defeat of several incumbent Democratic U.S. representatives. The Texas delegation now comprises 17 Democrats and 15 Republicans.

The bill's future is uncertain in the current special session because Senate rules are in place that require a two-thirds vote -- 21 of the 31 senators if all are present -- to bring a bill up for debate. Ten of the chamber's 12 Democrats and one Republican have said they would vote against debate, which would be enough to kill the bill.

That vote is expected Friday.

Gov. Rick Perry has signaled that he will call another special session to consider redistricting if it dies in this session, and Lt. Gov. David Dewhurst, who presides over the Senate, has said he might not employ the two-thirds provision if there is another session.

Senate Democrats have not ruled out boycotting the next session, as House Democrats did in the regular session last spring when they fled to Oklahoma to kill a redistricting bill in that session.

The state House has passed a redistricting bill in the special session, and differences in Senate and House versions eventually would have to be reconciled in a conference committee.

Both versions have similar effect on Houston-area districts, most notably slicing U.S. Rep. Chris Bell, D-Houston, out of his district to reduce his chances for re-election.

By drawing boundaries that move the homes of Bell and 95,000 other Anglos out of the 25th District while increasing the district's black population, Republicans say they have created a district that a black politician can win. But more than anything, they hope they have created a district that Bell cannot win.

"It wasn't drawn on a racial basis. It was drawn on politics. It was drawn to defeat Chris Bell," said Jim Ellis, a political aide to U.S. House Majority Leader Tom DeLay, R-Sugar Land. DeLay is pushing redistricting to increase Republican representation in the U.S. House.

DeLay and others argue that the Democratic majority in the Texas delegation is unfair in light of the GOP dominance of statewide offices and the state Legislature.

Bell spokesman Eric Burns said the congressman has not looked at his re-election chances in any of the GOP proposals.

The new 25th District would be numbered the 9th under the Senate map passed today, and the 25th designation would go to a district in South Texas.

Predominantly Anglo neighborhoods including West University Place, Braeswood Place, Meyerland and the Medical Center, no longer would be in the district. Bell's residence would be in the heavily Republican 7th District represented by U.S. Rep. John Culberson, R-Houston.

The new district picks up a large black population in the Sunnyside area from the southern end of the 18th District, represented by U.S. Rep. Sheila Jackson Lee.

The district's black voting-age population would be 36 percent, compared with 22 percent in the existing 25th.

The district would lose Anglo areas of eastern Harris County and pick up mixed ethnic neighborhoods around Alief.

The redrawn district would include almost half the people who are Bell's constituents now. But for Bell, who is out and who is in may be crucial.

Bell defeated Houston City Councilman Carroll Robinson 59 percent to 41 percent in the 2002 Democratic primary runoff. But redistricting computers at the Texas Legislative Council show the areas Bell won are mostly out of the proposed district, while the ones Robinson won are in.

Robinson, who is black, could not be reached for comment.

Democrats dismiss Republican claims that the new map creates a black district. They say Bell could move back into the district and win re-election as an incumbent.

Democrats make the same argument for Houston's 29th District, which is almost 60 percent Hispanic.

GOP proposals would cut U.S. Rep. Gene Green's residence out of the district, and Republicans say that would create an open Hispanic seat. But the district's voters have elected Green, an Anglo, for a decade.

Ellis said it may be difficult for minorities to defeat incumbents in the two districts, but he said it is not impossible.

"If they choose to move into those districts and take an opportunity from an African-American or a Hispanic, that is something they will have to deal with," Ellis said.

Ellis said the maps were driven in part by a recent U.S. Supreme Court decision that gives protected status to minority-influence districts -- those where Hispanic or black voters can affect the outcome of elections, even if an Anglo is elected. Bell's district and the 24th, represented by U.S. Rep. Martin Frost, D-Dallas, fit that category, Ellis said.

Now 11 districts are minority-influence or actually represented by minorities. Ellis said GOP redistricting proposals would retain that number as required by the federal Voting Rights Act.

Frost, a national Democratic leader, is a major Republican target. To eliminate his district and increase Republican representation in other parts of the state while retaining 11 minority districts, Republicans are drawing maps they say create minority districts in Houston -- the 25th and 29th -- and a new Hispanic district in South Texas.

Democrats do not agree that the GOP Republican proposals would be acceptable under the Voting Rights Act, designed to prevent dilution of minority voting strength.

Any redistricting plan that passes the Legislature almost certainly will face a court challenge.

Houston Chronicle reporter Clay Robison contributed to this report.