Jeez, sorry about the typos in the original entry. Not quite sure how I came to leave them in!
Isaac Asimov writes about his ancestry in the first few chapters of his autobiography, In Memory Yet Green, 1920-1954.
Some of the information is vague, as accurate records were not kept of Jews in Russia, and it is difficult to coincide the Jewish calendar with the Christian one.
I won't go into the transmutations of Tsarist Russia into Communist Russia.
Asimov's father told Asimov about his ancestry, beginning with his great-great-great grandfather, called Judah.
Judah "Asimov" - born approximately 1800.
This Judah and his descendants were dealers in rye or "winter grain" (aka Azimy khleb, which gave them their name, Azimov.) This Judah was, according to Asimov's father, "a great scholar."
This Judah had two sons (there may have been more children, but if so they were girls and therefore not worth mentioning in family records). The elder was Abraham Ber, the younger Moses Jacob, who died about 1899.
Abraham Ber was Asimov's great, great grandfather.
He lived long enough to see the birth of Asimov's father. He died when Asimov's father was 3 years old.
Ber had 12 children by his first wife. The first 11 died in infancy. The twelfth, Mendel, survived, and was Asimov's great grandfathet. (Asimov's father did not know the name of Abraham's first wife.) After this Asimov's first wife died, he married another woman. He had a son by this woman, named Judah. This Judah married and had a daughter, who apparently became a physician.
(Moses Jacob Asimov, Abraham Ber's younger brother, was a cantor. Moses only had two daughters.)
Judah Asimov (Asimov's father) had brown hair and brown eyes. ("There must have been a recessive gene," said Asimov, because he, his brother and sister all had blue eyes. His daughter had blond hair and blue eyes. (Asimov does not describe his son at all in these early chapters in his autobiography.)
Mendel's first-born son was Aaron Menahem Asimov, born about 1865. He was Asimov's grandfather.