Minimum goal expectation:

Understanding genealogy and ancestry of the male members with the surname Poropat whose families originated from settlements in municipality Lanišće in the mountainous Ćićarija area, in Istria County, Croatia.

Maximum goal expectation:

Understanding genealogy and ancestry of the male members with the surname Poropat in the Istria County (municipality Lanišće, municipality Poreč...), as well other parts of Croatia and world, including with the surname's variation like Poropatić (e.g. around Bjelovar, Glina, Petrinja), Parapatić (e.g. around Jastrebarsko, Sisak, Daruvar) among others.

Method:

Start with at least Y-DNA12 test ordered under "Male Line Testing", or Family Finder [autosomal DNA] + Y-DNA12 test ordered under "Combined Tests" so you can also use other FTDNA interactive tools, with which can be predicted general paternal haplogroup and likely relation of 95% probability within the past 29 generations (if based generations are 30-25 y. calculated since 1950 YBP, it's period 1080-1225 CE), or Y-DNA25 test with likely relation of 95% probability within the past 13 generations (1560-1625 CE). As FTDNA storage the sample for free 25 years, according to your personal wishes you can later upgrade when necessary to Y-DNA37, beside Y-DNA STR testing also specific Y-DNA SNP testing. However, the advisable Y-DNA STR test for a start is Y-DNA37, the minimum required Y-DNA12, maximum required Y-DNA67, while Y-DNA111 is unnecessary for the project because it indicates too recent common ancestor within the past 5 generations (1800-1825 CE).

Y-DNA STR test, with STR meaning short tandem repeat, is able to trace your direct paternal lineage within genealogical times and into historic times, i.e. recent father's paternal ancestry. It can clarify if related males who share the same surname will have identical or very close match Y-chromosomes, hence being useful to genealogists to match closely or distantly related individuals. With STR tests are obtained haplotypes (set of values for the tested DYS markers). 

If there are for e.g. matched 24/25 STR markers it indicates there is 95% probability of a most recent common ancestor within the past 20 generations (1350-1450 CE), or 23/25 within the past 27 generations (1140-1275 CE) and so on. In the case of matched 37/37 STR markers, it indicates there is 95% probability of a most recent common ancestor within the past 7 generations (1740-1775 CE), 36/37 within the past 10 generations (1650-1700 CE), 35/37 within the past 14 generations (1530-1600 CE) and so on. In the case of matched 67/67 STR markers, it indicates there is 95% probability of a most recent common ancestor within the past 6 generations (1770-1800 CE), 66/67 within the past 9 generations (1680-1725 CE), 65/67 within the past 14 generations (1530-1600 CE) and so on.

Y-DNA SNP test, with SNP meaning single nucleotide polymorphism, is able to confirm and identify the specific haplogroup and trace both ancient anthropological migrations and more recent prehistoric movements in a period of tens of thousands of years ago. Haplogroup would be a group of similar haplotypes that share a common ancestor with an SNP mutation, and it would be a (sub)clade i.e. branch on the Y-DNA tree. Your haplogroup tells much about your ancient origins. Testing SNP markers place you further down the branch on the Y-DNA haplotree and assist the scientific research on the Y-tree and haplogroup projects. SNP compared to STR has much slower mutation rate and should be tested if primary interest is more than the most recent generations of your family history (1 to 15). Without previous Y-DNA STR test, you are not able to view your haplotree or order Y-DNA SNP test. The specific SNP test might be recommended based on the initial Y-DNA STR test results, however, for now, there is no need for that. If anything, if exist financial possibility it is rather recommended, during discount period, most expensive but also most comprehensive and advanced Y-DNA test, Big Y-700, which includes both SNP and STR results. As can be seen in Project Statistics, two samples have done previous version Big Y-500.

Note that if you're male you can test both Y-DNA and mtDNA as well autosomal DNA, but if you're female you can only test mtDNA and autosomal DNA. Although mtDNA is passed down from females to both sons and daughters, sons do not pass down their mother's mtDNA to their children, hence males inherit and pass down direct father's Y-DNA, while females inherit and pass down direct mother's mtDNA. The autosomal DNA results mostly can contribute to understanding the genealogical connection between members mostly within the last 6 generations (180-150 years) possibly up to 8 generations (240-200 years).

DNA tests can be ordered through the project at:

https://www.familytreedna.com/group-join.aspx?Group=PoropatSurname