﻿ Relatedness Part 1
How closely am I related to everyone else?

All of my ancestors had two biological parents.  They may not have been married, the births may have been illegitimate, and the fathers identities may sometimes never be known, but they definitely had 2 parents.

This will change with cloning, but it still holds true today with my ancestors and I.

I will estimate that each of my ancestors generations spans 25 years.  That is, the average age of the parent was 25 when their child who was my ancestor was born.  That may be slightly too low of an estimate, but it will make the math of 4 generations per century much easier.

I had 512 individuals who were my  7th Great Grandparents.  I have found the names and birth dates of 9 of them.  I will demonstrate how close their average birth year is to 1725 later.

Therefore, I should have the following number of ancestors in each generation:

 Generation Number of Ancestors Approximate Birth Year Their Offspring  Are My World Population Estimates Me 1950 1 Parents 2 1925 Siblings 2 Grandparents 4 1900 1st cousins 3 Great Grandparents 8 1875 2nd cousins 4 2nd Great Grandparents 16 1850 3rd cousins 5 3rd Great Grandparents 32 1825 4th cousins 6 4th Great Grandparents 64 1800 5th cousins 7 5th Great Grandparents 128 1775 6th cousins 8 6th Great Grandparents 256 1750 7th cousins 9 7th Great Grandparents 512 1725 8th cousins 10 8th Great Grandparents 1,024 1700 9th cousins 11 9th Great Grandparents 2,048 1675 10th cousins 12 10th Great Grandparents 4,096 1650 11th cousins 13 11th Great Grandparents 8,192 1625 12th cousins 14 12th Great Grandparents 16,384 1600 13th cousins 15 13th Great Grandparents 32,768 1575 14th cousins 16 14th Great Grandparents 65,536 1550 15th cousins 17 15th Great Grandparents 131,072 1525 16th cousins f18 16th Great Grandparents 262,144 1500 17th cousins 19 17th Great Grandparents 524,288 1475 18th cousins 20 18th Great Grandparents 1,048,576 1450 19th cousins 21 19th Great Grandparents 2,097,152 1425 20th cousins 22 20th Great Grandparents 4,194,304 1400 21st cousins 23 21st Great Grandparents 8,388,608 1375 22nd cousins 24 22nd Great Grandparents 16,777,216 1350 23rd cousins 25 23rd Great Grandparents 33,554,432 1325 24th cousins 26 24th Great Grandparents 67,108,864 1300 25th cousins 423,000,000 27 25th Great Grandparents 134,217,728 1275 26th cousins 28 26th Great Grandparents 268,435,456 1250 27th cousins 29 27th Great Grandparents 536,870,912 1225 28th cousins 30 28th Great Grandparents 1,073,741,824 1200 29th cousins 400,000,000 31 29th Great Grandparents 2,147,483,648 1175 30th cousins 32 30th Great Grandparents 4,294,967,296 1150 31st cousins 33 31st Great Grandparents 8,589,934,592 1125 32nd cousins 34 32nd Great Grandparents 17,179,869,184 1100 33rd cousins 320,000,000 35 33rd Great Grandparents 34,359,738,368 1075 34th cousins

This shows that my number of ancestors would exceed the world population between 1200 AD and 1300 AD.

Would it be reasonable to assume that everyone should be my 29th cousin or closer from this?

Probably not, because the above numbers do not take into account the relatedness of each pair of ancestors.  That is, to what degree do cousins marry their cousins?

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