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(NOTE:  As the number of Y-DNA samples increases, the specific definitions of Haplogroups continue to improve and offer much more detail into the history of each Haplogroup.  Should the reader find the following definitions of Haplogroups (effective as of 2005) to be too vague, or if the Haplogroup being sought does not exist in the following list, it is suggested that the reader click here to be redirected to the Wikipedia (free online encyclopedia) website.  Once there, merely enter the entire Haplogroup being sought into the search engine and a complete, up-to-date definition of any Haplogroup should appear.)

FTDNA provided summaries of the following haplogroups in 2005.  The reader should keep in mind that the designation of Haplogroups will continue to change as additional data and research provides further insight into the distant origin of mankind.  For up-to-date information on current designations, click here to go to the Frequently Asked Questions on Haplogroups at the FTDNA site.

• Haplogroup B is one of the oldest Y-chromosome lineages in humans. Haplogroup B is found exclusively in Africa. This lineage was the first to disperse around Africa. There is current archaeological evidence supporting a major population expansion in Africa approximately 90-130 thousand years ago. It has been proposed that this event may have spread Haplogroup B throughout Africa. Haplogroup B appears at low frequency all around Africa, but is at its highest frequency in Pygmy populations.
• Haplogroup C is found throughout mainland Asia, the south Pacific, and at low frequency in Native American populations. Haplogroup C originated in southern Asia and spread in all directions. This lineage colonized New Guinea, Australia, and north Asia, and currently is found with its highest diversity in populations of India.
• Haplogroup C3 is believed to have originated in southeast or central Asia. This lineage then spread into northern Asia, and then into the Americas.
• Haplogroup D2 most likely derived from the D lineage in Japan. It is completely restricted to Japan, and is a very diverse lineage within the aboriginal Japanese and in the Japanese population around Okinawa.
• Haplogroup E3a is an Africa lineage. It is currently hypothesized that this haplogroup dispersed south from northern Africa within the last 3,000 years, by the Bantu agricultural expansion. E3a is also the most common lineage among African Americans.
• Haplogroup E3b is believed to have evolved in the Middle East. It expanded into the Mediterranean during the Pleistocene Neolithic expansion. It is currently distributed around the Mediterranean, southern Europe, and in north and east Africa.
• Haplogroup G may have originated in India or Pakistan, and has dispersed into central Asia, Europe, and the Middle East. The G2 branch of this lineage (containing the P15 mutation) is found most often in Europe and the Middle East.
• Haplogroup H is nearly completely restricted to India, Sri Lanka, and Pakistan.
• Haplogroups I, I1, and I1a are nearly completely restricted to northwestern Europe. These would most likely have been common within Viking populations. One lineage of this group extends down into central Europe.
• Haplogroup I1b was derived within Viking/Scandinavian populations in northwest Europe and has since spread down into southern Europe where it is present at low frequencies.
• Haplogroup J is found at highest frequencies in Middle Eastern and north African populations where it most likely evolved. This marker has been carried by Middle Eastern traders into Europe, central Asia, India, and Pakistan.
• Haplogroup J2 originated in the northern portion of the Fertile Crescent where it later spread throughout central Asia, the Mediterranean, and south into India. As with other populations with Mediterranean ancestry this lineage is found within Jewish populations. The Cohen modal lineage is found in Haplogroup J2.
• Haplogroup O1  is found at very high frequency in the aboriginal Taiwanese (possibly due to genetic drift). This haplogroup probably originated in East Asia and later migrated into the south Pacific. Individuals carrying this lineage are thought to have been important in the expansion of the Austronesian language group into Taiwan, Indonesia, Melanesia, Micronesia, and Polynesia.
• Haplogroup O2 has two primary lines, the 465 line and the M95 line. Both lines are found in Asia. The 465 line is at high frequency in Japanese and Korean populations and at low frequency in east Asia. The M95 line is found in Southeast Asian populations (Malaysia, Vietnam, Indonesia, and southern China).
• Haplogroup Q is the lineage that links Asia and the Americas. This lineage is found in North and Central Asian populations as well as native Americans. This lineage is believed to have originated in Central Asia and migrated through the Altai/Baikal region of northern Eurasia into the Americas.
• Haplogroup Q3 is the only lineage strictly associated with native American populations. This haplogroup is defined by the presence of the M3 mutation (also known as SY103). This mutation occurred on the Q lineage 8-12 thousand years ago as the migration into the Americas was underway. There is some debate as to on which side of the Bering Strait this mutation occurred, but it definitely happened in the ancestors of the Native American peoples.
• Haplogroup R1a is believed to have originated in the Eurasian Steppes north of the Black and Caspian Seas. This lineage is believed to have originated in a population of the Kurgan culture, known for the domestication of the horse (approximately 3000 B.C.). These people were also believed to be the first speakers of the Indo-European language group. This lineage is currently found in central and western Asia, India, and in Slavic populations of Eastern Europe.
• Haplogroup R1b is the most common haplogroup in European populations. It is believed to have expanded throughout Europe as humans re-colonized after the last glacial maximum 10-12 thousand years ago. This lineage is also the haplogroup containing the Atlantic modal haplotype (HG1).