>>The 144,000 Israelites that are sealed in chapter 7 are 12,000 from each tribe of Israel. These will be protected during the tribulation times from the trumpet and bowl judgments. They will survive through this time of judgment here on the earth. It does not say that they are all male virgins, it just says 12,000 from each tribe. It is likely that they are men and women of Israel. They are seen on earth.
The 12 tribes of Israel ceased to exist long ago. The bloodlines are all intermarried and some may have been eradicated completely.
God is able to preserve the Israelites all during their exile from their homeland, then brought them together as a nation in 1948. Their language, Hebrew, had not been spoken in 2,000 years, He brought that back too. I am sure that He can preserve the blood lines of the 12 tribes as well.
Because Jesus said that 12,000 from each tribe will be sealed, you can take it to the bank that He will.