The "Big 4" Cathcart Brothers
Anchor Point for many US and Australian Cathcarts
John | Matthew | James | Samuel
Background
These four brothers were all born in County Antrim, Ireland between 1763 and 1778. They were sons of either John (my best guess) or James Cathcart. I call them the "Big 4" as a convenient way to identify which John, James, Matthew or Samuel Cathcart I'm talking about. For example, my 4th great grandfather is James Cathcart, Sr. of the "Big 4."
We have excellent genealogical proof that these four were brothers, and can track each of them fairly well from birth to death.
Genetic Findings
Genetically speaking, we have at least four of us Cathcart cousins (descending from two of the above brothers, making us fifth cousins, removed by a generation or two) who have taken the yDNA test and are separated by only two markers in the 67 marker test.