Facts and Common Misconceptions

• No, haplogroups are not the same as haplotypes.
• Yes, all people living today fall into one of 18 main Y-DNA haplogroups on their paternal line, and one of 26 main mtDNA haplogroups on their maternal line.
• No, haplogroups will not show if you are related to someone (unless you count distant relationships from thousands of years ago).
• Yes, once you know your haplogroup, you will be able to view how your haplogroup migrated out of Africa and retrace their migration routes.
• No, haplogroups will not add people to your family tree or allow you to trace your surname (that’s the job of STR haplotypes).
• No, haplogroups will not tell you precise migration routes, it will show a broad migration route and population distribution.
• No, if you and someone else belong to the same haplogroup, it does not mean that you are closely related.
• Yes, once you know your haplogroup, you can often fine tune your branch of the haplogroup tree through subclade testing.
• No, you cannot confirm your haplogroup through STR testing or HVR1 testing.  A Y-DNA STR test and HVR1 test will often allow you to predict your haplogroup, but only a SNP backbone test will confirm the prediction.
• No, SNP backbone testing will not give you information about sub-clades.  It will confirm your haplogroup.  Once your haplogroup has been confirmed, a subclade panel test for your particular haplogroup will trace your subclade. 
• Yes, STR testing can give predictions for haplogroups and even some sub-clades, but the backbone test can only confirm the haplogroup, not the sub-clade.
• Yes, subclades are determined through SNP subclade testing (once your haplogroup has been confirmed)
• No, your haplogroup will not tell you if you are Welsh or Irish.  It will not tell you your ethnicity.  Although there are associations between ethnic groups and haplogroups, you must remember that haplogroups represent deep ancestry, tracing events from tens of thousands of years ago.  It does not tell you what your ancestors have been up to over the last few hundred years (that’s the job of Y-DNA STR markers, and applications such as Surname Projects, which will be the topic of another blog). 
• Yes, all people living in the world today are connected in the human phylogenetic tree.  Just like how all people belong to a certain blood group i.e. A, B, AB, O which can be determined through testing, all people also belong to a certain haplogroup which is unique to their ancestry, and their haplogroup type can be determined through genetic genealogy testing. 

From Genebase.com