How Many of Abraham’s Genes Did Christ Carry?
Abraham by Guercino (1657)
by Trent Dee Stephens, PhD, for the Come Follow Me lesson January 2-8: Matthew 1 and Luke 1
We read in John 8:33, “They [the Pharisees] answered him, We be Abraham’s seed, and were never in bondage to any man: how sayest thou, Ye shall be made free?” The Jews considered themselves the children of Abraham – his very seed – but, although they thought they knew what being the “seed of Abraham” meant, they really didn’t. They knew nothing of genetics – nor did anyone else until about 170 years ago – when Gregor Mendel discovered the basis of genetics.
We also read in Matthew 1:17, “So all the generations from Abraham to David are fourteen generations; and from David until the carrying away into Babylon are fourteen generations; and from the carrying away into Babylon unto Christ are fourteen generations.” Therefore, there were around 42 generations between Abraham and Christ. So how many of Abraham’s genes would Christ, or the Pharisees, likely have carried after 42 generations?
We have learned from the Human Genome Project, which was completed in 2003, that each human has around 20,000 to 25,000 genes. I will use the lower number for convenience sake. Each person has roughly 10,000 nuclear genes from his or her mother and 10,000 from his or her father. We have around 5,000 genes from each grandparent, 2500 from each great grandparent and etc. These can be written as 1/ 2 from each parent, 1/ 4 from each grandparent and 1/ 8 from each great grandparent. Notice that the denominator doubles each generation, so after 42 generations the probability of Christ having even one gene from Abraham would be 1/ 4,398,046,511,104. We need to keep in mind that the potential number of genes Jesus would have inherited from Abraham would have been only 10,000 genes, as He was descended from Abraham only on his mother’s side – with his paternal side being divine. The number just calculated for 42 generations is considerably larger than the 10,000 genes we would begin with at Abraham, so 10,000/ 4,398,046,511,104 is 2.273736754432321e-9 or roughly 0.0000000023. In other words, using this calculation alone, the probability of Christ having even one gene that he inherited from Abraham is 1 in 2.3 X 109 or around one in a billion.
However, this very low probability must be moderated by the fact that there weren’t 4.5 X 109 people descended from Abraham in 2000 BC – in fact, if we consider only Abraham’s descendants through Isaac, there was only one at that date – and half of his genes (10,000) were from Abraham. Isaac married Rebekah, who was Abraham’s great niece and thus would have shared about 2500 genes with Abraham (Genesis 25:15). Jacob would have inherited roughly 6500 Abrahamic genes. Jacob’s wife Leah was the daughter of Laban, Rebekah’s brother and, therefore, Abraham’s great nephew. So Leah would have brought around 1250 Abrahamic genes to the marriage. Therefore, Judah would have inherited roughly 3875 Abrahamic genes.
Both of Joseph’s ancestral lines presented in Matthew 1 and Luke 3 list his descent from Jacob through Judah and his son Phares. Phares was the son of Tamar, Judah’s daughter-in-law (1 Chronicles 2:4). Juda’s first wife was a Canaanitess (1 Chronicles 2:3), so there is no reason to assume that his second wife necessarily was a descendent of Abraham. Therefore, Phares would have carried about 1938 Abrahamic genes. We probably don’t know Mary’s ancestry but we can assume it was fairly similar to one of the lines shown for Joseph.
Abraham’s descendants numbered only a few hundred people even when Jacob’s (Israel’s) descendants left Egypt five hundred years after Abraham (see my blog from March 12: The Israelites in Egypt). We don’t know much about the marriages of Phares’ descendants as listed in Matthew 1 and Luke 3. We can assume that there were a combination of marriages both within and outside the Abrahamic line – probably following the model set by the earliest marriages of Abraham’s descendants. Even though the probability would certainly not reach one in a billion, as explained above, from Phares down to Joseph (or Mary) the number of Abrahamic genes would diminish by approximately half (depending on the amount of inbreeding in the line) each generation. There were 38 generations from Phares to Joseph, but it would take only about thirteen generations for the number of Abrahamic genes to fall below one in the subsequent generations of the lineage. Therefore, even though the Jews in Christ’s day could claim they were the seed of Abraham, with genealogies, like Joseph’s, that traced them back to Abraham, there would have been no genetic markers in those seeds tying them to the great patriarch.
Notice that the genealogies given in Matthew 1 and Luke 3 are those of Joseph – who was not the biological father of the Savior – perhaps one being Joseph’s paternal line and one being his maternal line (although maternal lines were rarely kept at that time). Some scholars have proposed that one or both genealogies may even have been fabrications.
My wife, Kathleen, was adopted, but she still follows the genealogy of her adopted parents. Likewise, Christ likely followed his “adopted” father’s genealogy. In Luke 3:8, before one version of Christ’s genealogy was given, John said to those who came to see him, “Bring forth therefore fruits worthy of repentance, and begin not to say within yourselves, We have Abraham to our father: for I say unto you, That God is able of these stones to raise up children unto Abraham.” Therefore, it actually doesn’t matter all that much whether or not a person can claim direct descent from Abraham, because we are told in Galatians 3:26-29, “For ye are all the children of God by faith in Christ Jesus. For as many of you as have been baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus. And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.”
So the Abrahamic covenant is not just for those who are “direct,” “literal” descendants of Abraham, but it is for all those who come unto Christ, no matter our actual genealogy. We are taught in the Church to do our genealogy because as we learn from Doctrine and Covenants 128:15, “And now, my dearly beloved brethren and sisters, let me assure you that these are principles in relation to the dead and the living that cannot be lightly passed over, as pertaining to our salvation. For their salvation is necessary and essential to our salvation, as Paul says concerning the fathers [Hebrews 11:40]—that they without us cannot be made perfect—neither can we without our dead be made perfect.” In Kathleen’s case, it doesn’t matter a lot which genealogy she follows – except that she is sealed to her adopted parents and it’s that family with which she has the strongest ties. She and her brothers know both their adopted family and their biological family, and are doing the genealogy for both families.
As you can see from what I have presented above, it doesn’t take very many generations, before the probability of having even a single gene from a given ancestor becomes diminishingly small. For example, after 15 generations, the probability of having one gene from a given ancestor is 20,000/32,768 = about 60%, after 20 generations the probability is 20,000/1,048,576 = around 2%. Twenty generations before today is about 400 years, pushing us back to roughly our Mayflower ancestors in 1622.
The Church guidelines for genealogy state, “Please do not submit the names of deceased celebrities and historical personalities, including those of royal or noble lineage or early LDS Church leaders and their families, or of persons born in European countries prior to A.D. 1500, regardless of your relationship to them. Though the names may not yet appear on the Ordinance Index, temple work for most of the people in these categories has already been done.”1
Six more generations beyond 1622, brings us to around 1500, where there is a 20,000/ 67,108,864 = 0.02 % chance of having any given gene from any ancestor living at that time. That information doesn’t mean we aren’t descended from a given person, it’s just that we are so far removed that all genetic connections are essentially lost. Typically, before 1500, European people fell into two categories: the roughly 1% of the population who belonged to the nobility and the 99% of the population who did not. The genealogies of the nobility were often meticulously recorded – indeed their class distinction often depended upon their ability to prove linage. The rest of the population was hardly recorded at all – usually only in church records of baptisms, marriages and deaths. Those records were usually brief and incomplete, and have often been lost to the ravages of time. As a result, modern genealogies often can be traced only to noble and royal families, which then pushes your family history very quickly “back to Adam.” Apparently, the medieval nobility and royalty considered it very important to link back to Adam, no matter how many of the links were fabricated. On the other hand, the main-stream population had little if any identified genealogical connections. As a result, modern genealogists can connect to noble lines and “go all the way back to Adam,” whereas connections through the non-noble population are almost impossible. That is one of the main reasons that nearly anyone you can link to before 1500 is probably nobility and their temple work was already done by someone in the past few generations of Church members.
Much of the genealogy that has been done in my family leads into noble European lines. Several of those lines lead back to Charlemagne and then “back to Adam.” The same is true for every other living person today of western European descent. In 2013, Peter Ralph, a molecular and computational biologist at UCLA and Graham Coop, a population geneticist at UC Davis, published a paper in PLOS Biology, entitled “The Geography of Recent Genetic Ancestry across Europe,” in which they concluded that everyone who lived in ninth century Europe, the time of Charlemagne, who had descendants, is the ancestor of every person living today of European descent.2 As we go back in time, each generation of our ancestors doubles in number so that our total number of ancestors becomes extremely large. But as Ralph and Coop point out, “However, as 1,000 years is about 33 generations, and 233≈1010 is far larger than the size of the European population [around 5.7 x 107 1,000 years ago], so long as populations have mixed sufficiently, by 1,000 years ago everyone (who left descendants) would be an ancestor of every present-day European.”3
The same conclusion can be drawn concerning Jesus’ royal descent from King David, who lived roughly 1,000 years before Christ. Jesus was indeed descended from King David, but so was every other person living in Judea at the time.
2. https://doi.org/10.1371/journal.pbio.1001555; see also Rutherford, Adam, So you’re related to Charlemagne? You and every other living European…The Guardian, May, 2015; https://www.theguardian.com/science/commentisfree/2015/may/24/business-genetic-ancestry-charlemagne-adam-rutherford