QJewish DNA

A related question is:

So first of all before we describe DNA findings it could be that DNA is often only reliable over relatively short historical periods. Since in some cases entire populations of animals and plants can change their DNA overnight through Genetic Transposon so could humans.
There may be environmental factors determining what the DNA will be.

Concerning DNA findings and Jews in conventional terms:

The Jews of today are quite thoroughly intermixed.
We may assume that the Ancient Hebrews had Near East DNA.
Ashkenazi Jews have mt(female) DNA that is ca. 60% Southern European especially from Tuscany and southern France. On the other hand Ashkenazi Y(male) DNA is ca. 60% Near Eastern.
Jewish Yemenite mtDNA is mostly Arab whereas the YDNA is mostly Levantine Near Eastern.
Sephardic DNA is similar to Ashkenazi but with more mixed admixtures i.e. where the Ashkenazi have Tuscan admixture Sephardim have North African or other local input.
There are numerous articles on these matters but the overall picture is usually as described above.

For Ashkenazim the so-called "Rhineland Hypothesis" fits present knowledge better than any other. According to this Jews from the Holy Land came to southern Europe when there was an "historical window" probably some time prior to 500 CE) in which numerous converts were accepted especially women.
There was initially a large number but due to persecutions etc. the population was quickly reduced. The small number that remained intermixed with each other and then moved from the Rhineland region in Germany to the east. This seems to be what happened but in addition to this
in the east they mixed again with other Hebrews and converts who had emerged from Persia and Khazaria. The population experienced periods of contraction and expansion.
The result was that no matter where they originally came from they were all ultimately mostly related to each other.
This means that no matter how many converts had been accepted in the past their descendants were all to some degree or other the offspring of the Hebrew original stock.
So what exactly are they?
Jews derive from the people of Judah (Judea) meaning the Tribes of Judah, Benjamin, Levi, and smaller numbers of the others.
Jews are adherents of Judaism, of the Biblically derived Jewish Religion.
This is based on the Bible.
Scripture says that the Land of Israel is the eternal possession of the descendants of Abraham, Isaac, and Jacob.
Other Prophecies were also made concerning them. All promises to the ancestors included converts alongside them.

Ruth the Moabite was the prototype of a convert and also the ancestress of King David.

Ruth (CTC) 1:
16 AND RUTH SAID, "DO NOT ENTREAT ME TO LEAVE YOU, TO RETURN FROM FOLLOWING YOU, FOR WHEREVER YOU GO, I WILL GO, AND WHEREVER YOU LODGE, I WILL LODGE; YOUR PEOPLE SHALL BE MY PEOPLE AND YOUR GOD MY GOD.
17 WHERE YOU DIE, I WILL DIE, AND THERE I WILL BE BURIED. SO MAY THE LORD DO TO ME AND SO MAY HE CONTINUE, IF ANYTHING BUT DEATH SEPARATE ME AND YOU."

In Hebrew the word for convert is "Ger" which is often translated as "stranger."

Leviticus 19:
34 THE STRANGER THAT SOJOURNETH WITH YOU SHALL BE UNTO YOU AS THE HOME-BORN AMONG YOU, AND THOU SHALT LOVE HIM AS THYSELF; FOR YE WERE STRANGERS IN THE LAND OF EGYPT: I AM THE LORD YOUR GOD.

In the End Times the convert will receive a portion according to whatsoever Tribe they sojourned amongst.

Ezekeil (TCT) 47:
21 AND YOU SHALL DIVIDE THIS LAND AMONG YOURSELVES ACCORDING TO THE TRIBES OF ISRAEL. 22 AND THAT WILL BE WHAT YOU ALLOT AS A HERITAGE, FOR YOURSELVES AND FOR THE STRANGERS WHO DWELL IN YOUR MIDST, WHO WILL BEGET SONS IN YOUR MIDST, AND THEY WILL BE TO YOU AS CITIZENS AMONG THE CHILDREN OF ISRAEL; WITH YOU THEY WILL INHERIT OF THE INHERITANCE IN THE MIDST OF THE TRIBES OF ISRAEL. 23 AND IT SHALL BE IN THE TRIBE WITH WHICH THE STRANGER SOJOURNS, THERE YOU SHALL GIVE HIS INHERITANCE, SAYS THE LORD GOD.

Possessing the Land is contingent to a degree on keeping the Law or at least central portions of it.
The Law was given to descendants of Israel as well as to converts. Throughout the Bible the inclusion of converts prepared to keep the Law is repeated and emphasized.

Genesis (CTC) 17:
7 I WILL ESTABLISH MY COVENANT BETWEEN ME AND YOU AND YOUR DESCENDANTS AFTER YOU THROUGHOUT THEIR GENERATIONS FOR AN EVERLASTING COVENANT, TO BE GOD TO YOU AND TO YOUR DESCENDANTS AFTER YOU.
8 I WILL GIVE TO YOU AND TO YOUR DESCENDANTS AFTER YOU, THE LAND OF YOUR SOJOURNINGS, ALL THE LAND OF CANAAN, FOR AN EVERLASTING POSSESSION; AND I WILL BE THEIR GOD.
9 GOD SAID FURTHER TO ABRAHAM, NOW AS FOR YOU, YOU SHALL KEEP MY COVENANT, YOU AND YOUR DESCENDANTS AFTER YOU THROUGHOUT THEIR GENERATIONS.
10 THIS IS MY COVENANT, WHICH YOU SHALL KEEP, BETWEEN ME AND YOU AND YOUR DESCENDANTS AFTER YOU: EVERY MALE AMONG YOU SHALL BE CIRCUMCISED.

Today the Jews in the Land of Israel comparatively speaking do keep much of the Law. Everyone is circumcised. More than 70% fast on Yom Kippur (Day of Atonement); about 60% keep some degree of Kashrut in foodstuffs in their home; more than 20% endeavor to keep as much of the commandments as they can; about 20% send their children to religious schools; close to 10% (mainly Hareidim) learn Torah full-time; and much more.

The Hebrews divided into two separate sections. Judah became one part, the Lost Ten Tribes the other.

Other promises included becoming a great and mighty nation. These were to involve the Lost Ten Tribes. The exiled Israelites from the Ten Tribes were to become one of the most numerous groups of people on earth (Genesis 15:5, 22:17, 24:60, 32:12, Numbers 23:10, Deuteronomy 1:11, Isaiah 10:22, 24:16, 26:15, Hosea 1:10); to be the most powerful (Genesis 27:9, Numbers 24:7, Michah 5:7-9), to be the richest, to possess the most mineral and agricultural resources (Genesis 27:28, 49:25, Deuteronomy 33:13-16, Hosea 2:8), to live in the best places (Isaiah 41:8-9), to be in islands (Isaiah 42:4, 49:1-6 Jeremiah 31:9-10), peninsulas (Jeremiah 31:8), and at continental extremities (Deuteronomy 33:13, Isaiah 24:16, 26:15, 41:8-9, 49:6), to be sea-farers (Isaiah 42:6). They were to be found especially to the north and west of the Land of Israel, to gain control over strategic points regarding their potential adversaries (Genesis 22:16-17, 24:60), to be like a lion, and unicorn (Numbers 24:8-9), and bald-headed eagle (Micah 1:16). They were also to be largely unaware of their Israelite identity and to practice a non--Jewish religion (Hosea 2:8, 2:13, 2:16 11:12). Judah in the End Times would not know who they were (Isaiah 49:21). Scripture gives numerous other identifying characteristics that taken as a whole can only fit THE one group of people that were to be found in Western Europe especially in Britain and its offshoots in North America, etc.
The descendants of the Ten Tribes are to be found among the English-speaking Peoples and those of Western Europe.
The Lost Ten Tribes were assimilate among the Gentiles in order to elevate them from within.
In the future the two halves will re-unite.
Judah was to inherit the Land before the others. This involved taking in converts, keeping the Law, and initiating development of the Land..