It would seem that those trying to promote the belief that the original Cohen and Israelite ydna Haplogroup was J downplay the significance of R1b among both Cohenim and Leviim as well as in the general population of Ashkenazi and Sephardi Jews. In order to bring down the percentage among Ashkenazim they exclude the Dutch Ashkenazi from their figures. Eupedia claims that among the Sephardi R1b is only 13 percentage when it is closer to 30 percent according to other sources. Studies on Converso descended communities show over 50 percent of R1b.
The Jewish R1b project lists many Ashkenazi Jews in the R1b haplogroup and much of it of a middle Eastern variety (Ht 35) to which many of the R1b Cohenim and Leviim belong. It is the J groups that are convert bloodlines in Judaism. The J1 come from Arab and Samaritan converts and J2 from Samaritan and other non-Israelite Middle Eastern converts. J and I are the haplogroups of the descendants of Ishmael. I ydna being the haplogroup of the Royal Assyrians (who fled to Samara in Russia and then into Europe) who branch into the Sarmatians and Vikings.
The I among Jews represents a Royal Assyrian input. R1a is Josephite and among the Ashkenazi this comes from the Khazar input. G is a Syrian input and much of J and E is from Samaritan origins. T and L is Edomite and Q is Benjaminite. The descendants of Abraham belong to IJK and the descendants of Jacob belong to NOP. There is a small percentage of K (Midianite/ Kenite) and O3 (Gadite) among Sephardi and Converso Jews. The R1b among Jews mainly comes from the Tribe of Judah, the House of Aaron and Levi, the Tribe of Simeon and the Royal House of David.
Some of the clans or clades of Judah and Levi are found among Ht 35 and some among Ht 15. R1b L23 represents those R1b Israelites of the Kingdom of Judah and the Kingdom of Israel from the 12 (13) Tribes. R1b L51 represents those R1b Israelites and Judaites taken into Exile by Assyria and R1b Z2103 represent the R1b Jews of the continuing House of Judah with R1b clades from Judah, Levi, Cohenim and the Royal House of David. The Tribe of Simeon (DF27) went to Spain (Iberia) and some of their clans such as R1b SYR2627 reembraced Judaism as did some of the Reubenites (Radhan Jews) of R1b L2 and L4 (R1b U152) and some of the Zebulonites of L47 (R1b U106).
It is important to note when analyzing the dna evidence that dna may be affected by environmental factors and cataclysmic events in which the mutation rate may be rapid and a group of the same dna haplogroup may experience a mutation change (a loss of information) rather than just an individual. Dna studies are still in their infancy and it is not clear how much environmental factors affect dna. The Patriarch Jacob was the NOP ancestor who lived about 3900 years ago.
In the days of Joseph in 1766 BC the nuclear winter that caused the 7 year famine was most likely the time many of the mutations occurred across the NOP Israelites as well as the other haplogroups. Some of these mutations affected the individual and some the family group. Jacob's sons by the sisters Leah and Rachel all have P-M45 but his children by the concubine sisters Bilhah and Zilpah do not. It seems that the mutations for R and R1 occurred in Joseph and his half brothers by his mother's sister Leah's descendants but not in his brother Benjamin's descendants. It would seem that all the sons of Leah that went to Egypt the first time and Joseph who was in Egypt were affected (or at least their children) whereas Benjamin (or his sons) who at this time remained with his father in Canaan did not receive these mutations.
The sons of Leah also received the mutation for R1b whereas Joseph (a son of Rachel) did not but his sons Ephraim and Manasseh inherited the R1a mutation. Different mutations occurred in Jacobs four sons by his two concubines. The sons of Bilhah, Naphtali and Dan were the ancestors of N haplogroup and the sons of her sister Zilpah, Asher and Gad were the ancestors of the O haplogroup. Estimating the age of haplogroups using a standard rate does not take into account mutiple mutations occurring around the same time and the different rate for different haplogroups. Many mutations occurred as a result of the cataclysmic events of 1960 BC (causing Abraham and his generation to age more rapidly and Isaac's degenerative blindness according to the Jewish tradition) and then again after 1766 BC in the time of Joseph.