In all but the reproductive cells, all human being cells have 46 chromosomes. However, only male cells have a Y-chromosome. Sons inherit the Y-chromosome from their fathers, who in turn inherited their Y-chromosome from their fathers and so on. The Y-chromosome can remain totally unchanged for many generations, so males will likely have a Y-chromosome which is identical to their paternal g-g-g-g-g-g-grandfathers'. Sons, brothers and male paternal cousins also normally share the same surname making Y-chromosome DNA testing a valuable genealogical tool.

Y-chromosome DNA testing is most powerful when used in conjunction with existing paper records in trying to prove (or disprove) a theory or connection between two males with the same or similar surname. If two males are determined to have the same Y-chromosome, they are very likely to be related even though they may only share a g-g-g-g-g-g-grandfather. Conversely, if the Y-chromosomes of two males are not very nearly identical, they are not closely related even though they may share the same surname.

The Y-chromosome is present in the nuclei of every living male's cells. Like all chromosomes, the Y-chromosome is made up of a very long DNA molecule carefully wrapped around some proteins. A DNA molecule is a two corkscrew-like (double-helix) structure connected by lots of smaller cross-links.

If these 'corkscrews' were stretched, untwisted and flattened, the double helix would become a simple ladder-like structure. The DNA cross-links of the untwisted and flattened ladder are very frequently portrayed as color coded rungs.

All the rungs are made from four compounds. Each half of a rung is 'complementary' to the other half. Whenever a blue segment (representing the chemical compound Thymine) occurs, a red segment (representing the chemical compound Adenine) is the other half. Yellow (representing the chemical compound Cytosine) complements green (representing the chemical compound Guanine).

Thus, the DNA chain shown above becomes the sequence of letters:

T C T G C T A G A C T A T G G A G A ....

Only one side needs to be written because the other side of the 'ladder' is its complement. Passing along the Y-chromosome from father to son means that the sequence of letters representing the Y-chromosome DNA molecule cross-links remain the same.

DNA is often called the 'molecule of life'. A portion of a DNA strand contains the code words that help build proteins. These proteins define what we are and keep our bodies functioning. A much larger portion of a DNA strand is referred to as 'junk' because it contains no bodily function information. However, certain special markers along the DNA strand in these 'junk' regions are useful in pursuing the genealogy of a person. At these markers (called STRs for short tandem repeats and designated by a DNA Y-chromosome Segment or DYS number), the sequence of  the DNA ladder repeats itself many times.

As an example, the DNA STR marker named 'DYS391' may be a sequence like: TCTG TCTG TCTA TCTA TCTA TCTA TCTA TCTA TCTA TCTA TCTA TCTG CCTG CCTG, where TCTA is repeated 9 times. For this example, the 'DYS391' marker would be recorded as DYS391 = 9. Because the Y-chromosome is special in that it doesn't undergo 'shuffling' with each new generation, the number of repeats in our example DYS391 will tend to remain 9 from generation to generation, including paternal cousins for many generations. The 'DYS391'  marker repeats can be anywhere between 7 and 14. The variations of repeats are known as alleles. Two individuals are said to have alleles in common when the number of marker repeats is the same.

Very infrequently a mutation occurs and the number of  repeats will increase or decrease, usually one at a time. That is, a father may have DYS391 = 9 and his son has DYS391 = 10. The appearance of this extra TCTA demonstrates Darwin's 'Theory of Evolution' at work on a molecular scale! Without these genealogically important mutations, every male would have exactly the same Y-chromosome. Because mutation occurs, we can not only determine if two males are most likely closely related, but because the frequency of these changes can be estimated, we can estimate when the most recent common ancestor (MRCA) lived.

 Examination of a number of STR markers is required to assess when the most recent common ancestor (MRCA) may have lived. When a number of STR markers are tested, a 'haplotype' is obtained. A 'haplotype' is the sequence of numbers for the markers tested. Using a 21-marker test, an individual's  haplotype might look like, where the top row are the STR markers tested and bottom row are the STR alleles.

As the following depiction shows, because an STR may have mutated a related cousin may or may not have an identical haplotype. However, because the probability of a mutation is low, two closely related cousins will likely have few haplotype differences.

The 21-marker haplotypes for these cousins might then look like:

Reading across, most of the alleles are the same except for the marker highlighted in gray. Cousin 3 shows a mutation at DYS392. The results follow the paper genealogy in that Cousins 1 and 2, who match each other at all 21 markers, are closely related and Cousin 3 is related, but more distantly so.

For 21 STR markers, the following table gives the number of generations between "Most Recent Common Ancestors" on average and within a 95% confidence interval versus haplotype mismatches.

More mismatches equates to a more distant relationship. With 21 markers, identical haplotypes or haplotypes with one difference usually means a closely related individuals. Two mutations between 21 marker haplotypes is somewhat indeterminate while three mutations usually excludes the possibility of a close relationship between two individuals.

Armed with this understanding of Y-chromosome DNA, the Mohler Surname Project is attempting to answer some of the unanswered questions about the origins of Mohlers in America. Using Y-Chromosome DNA testing of several  well documented descendents of Henry Mohler b. 1728, we should be able to determine Henry's  modal  haplotype. Similarly from testing several descendents of Ludwig Mohler, who immigrated to America in 1730, we can compute Ludwig's modal haplotype. Comparing these derived haplotypes, we can determine how closely related these early immigrants appear to be. With DNA haplotypes from members of the Mohler family that now live in the Basel, Switzerland area, we can also assess the likelihood of a Mohler migration from the Basel, Switzerland area to Ephrata, PA. From DNA testing of descendents of Henry Mohler (1711 - 1797) who bought land in Berwick, York County, Pennsylvania in 1753 and later moved to Frederick, Maryland, along with testing of George Adam Moler descendents and  testing of descendents of John Mohler, husband of Magdaline Rinehart and proprietor of Weyer's Cave, we may finally determine whether these Mohler/Molers are closely related to the descendents of Henry Mohler b. 1728.

Preliminary, interesting results are in. Not surprisingly, we can say with a high degree of certainty that Henry Mohler born in 1711, Henry Mohler born in 1728 and Ludwig Mohler born in 1696 are very closely related to one another. The values of  43-marker haplotypes showed at most a two marker difference between each of the documented Mohler descendents tested and a common "Mohler modal haplotype" that has at most only a one marker difference.

With a greater degree of certainty, we can say the individual identified as George Adam Moler is not closely related to 1711 Henry, 1728 Henry and Ludwig Mohler. Only 14 of the 43 Moler descendents markers matched the 43 Mohler descendents markers.

General Genealogy Links

The Genealogy Home Page	RAND Genealogy Club
Family Tree Maker's Family Finder Index	Cyndi's List of Genealogy Sites
Best Genealogy Links on The WWW	Roots Surname List Name Finder
National Archives and Records Administration	Genealogy is My Hobby!!

Pennsylvania Dutch & Mohler Related Links

The Palatines to America Homepage	On-line Immigrant Ancestor Register
Pennsylvania Passenger Ships' Lists	List of Ships to Philadelphia
On The Trail Of Our Ancsestors	Pennsylvania Dutch Welcome Center
Ephrata John Landes Family	Royer Family in America
Mohler Family Names	Mohler Family Surnames
Thistle Ship List	Elder Michael Frantz Baptisms
Brethren Church Homepage	Brethren in America
Brethren Church European Origin	Brethren Church History & Genealogy

Palatine & Pennsylvania-Dutch Genealogy

Maps

Mohlers Church	Mohler Country
Early Pennsylvania Map Collection	East Cocalico Map c1790
Vicinity MapBlast! Map Launcher Page	Stanford U. Searchable Map Gopher
U.S. Gazetteer	USGS Mapping Information

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