Caudill YDNA Project

Last Updated: May 21, 2015.

The Caudill YDNA Project began as a whim back in 2004 with a meager three samples and has now grown to 44 participants.  While the ‘old-timers’ are well known for proliferation of the message that the various spellings of the surnames ‘ain’t kin’, the genetic analysis has revealed a wholly different, and irrefutable, story.  The project has gathered and analyzed samples from not less than seven variant spellings of the surname, specifically:  Caudel, Cordell, Caudill, Caudell, Cordle, Cadle, and Cottle.

One surprising and unforeseen circumstance that emerged through the project development was the number of individuals coming forward seeking to use YDNA testing as a means of revealing the truth of their ancestry.  Ten of our participants have surnames that are not derivative of the core group (American Soundex Code = C340).  In at least one instance, a participant successfully located his previously unknown half-brother through the project’s efforts.

We’re using YDNA to establish ‘RELATEDNESS‘ by determining the mathematical probability of a Common Ancestor. Specifically, we are attempting to calculate the probability of Time to Most Recent Common Ancestor (TMRCA).

Technical Discussion:

If you have an interest in a overly simplified understanding of Y-DNA, see the Technical Discussion at the bottom of this page.  I separated this from the rest of the page knowing most folk couldn’t really care less about the technical aspects, yet others, will enjoy a simple explanation.


1775Jeremiah Caudill
Abt. 1779
1795Jesse P. Caudill
1800John B. Caudill
1815James Robert Caudill
1825Hugh B. Caudill
1840James Harrison Caudill
John Allen Caudill
1855Thomas Jefferson Caudill
1870Fielden Bealer Caudill
1875Alford Martin Caudill
1885Edward Floyd Caudill
1895Linnie Famon Caudill
1915Edward Thomas Lee Caudill
1920Zeb Vance Caudill
1925Leonard Frank Caudill, Jr.
1930Avery Chester Caudill
David Lee Caudill
1940Bealer Vance Caudill
1950Larry Dean Caudill
1955Lenny Famon Caudill
Edward Lee


By example:

Participant #49444 is the 4th great grandson of Jesse P. Caudill born about 1795 in Wilkes County, North Carolina.  Counting his birth, that’s seven generations.  Participant #150729 is the 4th great grandson of Jeremiah Caudill born about 1779 in Wilkes County, North Carolina.  Counting his birth, that’s the same seven generations.  Using various documents, we can ‘prove’ the lineages back to these two ancestral men for these two familial lines.  Without any genetic testing whatsoever, we know from the outset that these two participants do not share a Common Ancestor for seven generations.  We cannot prove beyond a shadow of doubt who Jesse’s father was, nor Jeremiah’s.

Looking at twenty five markers, (Table 1), we quickly observe that these two men have identical YDNA when measured at these twenty five locations on the Y chromosome. Knowing beyond a doubt they’re related, we can next calculate the probability of a ‘Most Recent Common Ancestor’.  This calculation is performed using digital tools available at our project host,

In comparing Y-DNA25 markers, which show 0 mismatches, the probability that (49444) and (150729) shared a common ancestor within the last…

…8 generations is 37.69%.
…12 generations is 75.81%.
…16 generations is 90.61%.
…20 generations is 96.35%.
…24 generations is 98.58%.

And there you have it!  Jesse P. Caudill and Jeremiah Caudill are DEFINITELY related.  Taking a generation to be 25 years on average, there’s a 75% chance that they share a common ancestor within 100 years of their birth.  (12 generations – 8 generations = 4 generations, multiplied by 25 years per generation).

Table 1: Twenty Marker Comparison Participant #49444 and Participant #150729.

Marker Number

Descendant of

Jesse P. Caudill

Descendant of

Jeremiah Caudill

DYS393 13 13
DYS390 23 23
DYS19 13 13
DYS391  11 11
DYS385  11-14 11-14
 DYS426  12 12
 DYS388 12 12
DYS439 12 12
DYS389i 13 13
DYS392 13 13
DYS389ii  29  29
DYS458  17 17
DYS459  9-10 9-10
 DYS455  11 11
DYS454  11 11
DYS447  24 24
 DYS437  15 15
DYS448  19 19
DYS449  29 29
DYS464  15-16-18-18 15-16-18-18

A ‘somewhat’ Technical Discussion:

John A. Blair is still the master at making this stuff understandable.  Check out his site at BLAIR DNA Project.

During conception, you received a total of 46 chromosomes — 23 from your mother and 23 from your father.  As these chromosomes ‘paired-up’ to become you, all the genetic information necessary to make ‘you’ was present.  As each new cell of ‘you’ subsequently reproduced, a precise copy that original pairing was re-manufactured in the new cells (all cells in our bodies, except red blood cells, contain an exact copy of our individual DNA).  So in short, DNA is a chemical inside the nucleus (center) of every cell that contains our particular and individual genetic instructions.  DNA is an acronym for DEOXYRIBONUCLEIC ACID.



Figure 1: Typical Human Cell and Chromosome

In Figure 1, the you’ll see a human cell drawn and its nucleus.  In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46.  The CHROMOSOMES are contained within the cell’s nucleus, hence, the term ‘NUCLEAR DNA‘.  Chromosomes run in pairs and come in a large variety of sizes and configurations.  In this diagram, there are two CHROMATID‘s, forming what resembles a letter ‘X’, intersecting at the CENTROMERE.  The strands of DNA are depicted as a double helix within Centromere.  One GENE is simply one short segment of this double helix.  AUTOSOMAL chromosomes are those that contain no gender instructions (information).  22 of the 23 chromosomes you received from your mother and father are autosomal. Therefore, 44 of the 46 chromosomes you received from your parents play no role in determining your gender.  The 23rd chromosome is the center of our interest — more precisely, we’re interested in the paternal male’s 23rd chromosome (Y-Chromosome).

To aid the understanding of the how grossly over-simplified this diagram is, in Chromosome #1, there are 3,000 genes and over 24,000,000 base pairs.  The 23 chromosomes are numbered 1 through 22, respectively, then the 23rd chromosome is either ‘X-Chromosome’ or ‘Y-Chromosome’ based upon gender.  Y-Chromosome contains over 200 genes and over 50,000,000 base pairs and 50% of those bases have been determined (Source: National Center for Biotechnology Information, U.S. National Library of Medicine).

The 23rd chromosome, the Y-Chromosome, is sometimes referred to as the ‘Sex Chromosome’.  Reason being, this chromosome determines your gender.  Females only have a ‘X-chromosome’ to contribute during conception while males have both ‘X-chromosome’ and ‘Y-chromosomes’ to donate.  If your father gave you a ‘X-chromosome’, you’re a female (X+X).  If your father gave you a ‘Y-chromosome’, you’re a male (Y+X).  Considering that this contribution is completely random, it’s now easy to understand why there are about as many females as males in the world population (your gender determination was basically a coin-toss during conception).  The foregoing explanation leads to an understanding that only males have a Y-chromosome (e.g. YDNA).

Chromosome (2)


Figure 2: Double Helix and Base Pairs

U.S. National Library of Medicine

Observe in Figure 1 the section of chromosome labeled DNA DOUBLE HELIX and BASES.  Figure 2 is an enlarged view of this section which includes the four bases: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).  These four bases contain your genetic coding.  DNA bases pair up with each other, A with T and C with G, to form the units called base pairs.

The light blue helical ribbons in Figure 2 are composed of sugar and phosphate molecules.  The horizontal ‘ladder rungs’ of DNA (the BASE PAIRS) are attached to these spiraling ribbons.  The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder (sugar phosphate backbone) — each base is attached to the backbone by a sugar molecule and a phosphate molecule.

Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix.

Let’s pretend that a particular nucleotide is located at a defined position on the double helix.

STR markers

A chromosome contains sequences of repeating nucleotides known as short tandem repeats (STRs). The number of repetitions varies from one person to another and a particular number of repetitions is known as an allele of the marker. An STR on the Y chromosome is designated by a DYS number (DNA Y-chromosome Segment number). The example below shows the allele of Rumpelstiltskin’s DYS393 marker is 12, also called the marker’s “value”. The value 12 means the DYS393 sequence of nucleotides is repeated 12 times—with a DNA sequence of (AGAT)12.

Conceptually, father’s pass an EXACT copy of their Y-chromosome to their sons.  Their sons pass an EXACT copy of their Y-chromosome to their sons, and so forth, and so on — ‘Conceptually’, my YDNA is an absolutely EXACT copy of my paternal great-great-great-grandfather’s YDNA.  Herein lies the value of YDNA research — if you’re a male and a paternal great-great-great-grandson of John Caudill, and I’m a male and paternal great-great-great-great-grandson of the same John Caudill, in theory, our YDNA should match EXACTLY.  We can therefore establish ‘relatedness’ and ‘common ancestry’ between two males, separated by multiple generations, by comparing their genetic fingerprints.  Let’s hold off on the topic of ‘mutations’ for just a short while.


Each chromosome carries many genes; humans’ estimated ‘haploid’ protein coding genes are 20,000-25,000, on the 23 different chromosomes.




Y-DNA testing looks at the DNA in the Y-chromosome, a sex chromosome that is responsible for maleness. All males have one Y-chromosome in each cell and copies are passed down (virtually) unchanged from father to son each generation.

YDNA tests specific markers on the Y-chromosome of your DNA known as Short Tandem Repeat, or STR markers. Because females do not carry the Y-chromosome, the Y-DNA test can only be used by males.

Males only.