Understanding Results: Population Finder

  1. What is the Population Finder Tool? faq id: 1037
  2. What reference populations are used? faq id: 1039
  3. What is the source of the reference populations? faq id: 1040
  4. Does the program use other customers’ data in comparisons? faq id: 1041
  5. Can I use the Population Finder tool to prove a family tradition? That is, will Population Finder tell me if I’m Jewish, Native America, etc.? faq id: 1042
  6. How many autosomal SNPs does the Population Finder tool use? faq id: 1046
  7. How does Population Finder determine the percentages of different ancestries? faq id: 1049
  8. How many ancestral populations does the Population Finder tool show? faq id: 1050
  9. How do you decide how many populations to show? faq id: 1051
  10. What is the population survey? Why am I being asked to fill it out? faq id: 1052
  11. Does the Population Finder program use DNA segments the way Family Finder does? Does it use individual SNPs? faq id: 1053
  12. Does the Population Finder tool use non-autosomal DNA results? faq id: 1054
  13. How many generations in the past do Population Finder results reflect? faq id: 1166
  14. Why have my results changed? faq id: 1167
  15. Some of my relatives have results that show both a larger group and a subset in parenthesis. Others only show the larger group. What is the difference? faq id: 1168
  16. My results show two different populations. One seems to be a subset of the other. Why is this? faq id: 1169
  17. How can I tell which side of my family (mother or father) a population match comes from? faq id: 1173
  18. Can the Population Finder tool determine the specific country from which my ancestors originated? faq id: 1174
  19. The tool says 35% of my ancestry comes from the Southern Europe region. What does that tell me in terms of my shorter term ancestry vs. longer term ancestry? faq id: 1175
  20. This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working? faq id: 1176
  21. In the Population Finder program's analysis, are there any regions or populations that are particularly hard to tell apart? faq id: 1177
  22. My results include a list of countries. Is my ancestry from all of these countries? Is it always from one of them? faq id: 1178
  23. Is the percentage an admixture amount or a match probability? faq id: 1184
  24. Why don't the percentages from each population add up to 100%? faq id: 1185
  25. What is the Margin of Error? How is it determined? faq id: 1186
  26. What is the impact of the Margin of Error on the conclusions I can draw? faq id: 1187
  27. What does it mean if the Margin of Error is very high? faq id: 1188
  28. I have a family tradition of Native American ancestry. Is the Population Finder tool able to detect it? faq id: 1204
  29. I would like to prove a family tradition. How many generations in the past can the Population Finder detect? faq id: 1205
  30. All of my genealogy comes from Europe. Why do my Population Finder results include Africa? faq id: 1208
  31. All of my genealogy comes from Europe. Why do my Population Finder results include America? faq id: 1209
  32. All of my genealogy comes from Europe. Why do my Population Finder results include East Asia? faq id: 1210
  33. All of my genealogy comes from Europe. Why do my Population Finder results include Middle East? faq id: 1211
  34. All of my genealogy comes from Europe. Why do my Population Finder results include South Asia? faq id: 1213
  35. I had my Family Finder results analyzed using a third party service. Why do the results differ from Population Finder? faq id: 1668

Questions and Answers

  1. What is the Population Finder Tool? faq id: 1037

    The Population Finder tool is a way of looking at your genetic history. It uses a process called principal component analysis (PCA) to provide biogeographical analysis of your autosomal DNA.

    Simply put, it compares your genetics to that of global populations. These are organized by continental groups (Africa, The Americas, East Asia, Europe, Middle Eastern, Oceania, and South Asia). The Population Finder results show the amounts of your ancestry from one to four of the continental groups.

    Note: The seven continental groups are based on genetic similarity. They do not precisely match geographical continents.

  2. What reference populations are used? faq id: 1039

    The Family Tree DNA world DNA population database uses samples from scientific studies.

    Below is the list of currently approved subgroups and populations for the continental groups. As our scientific advisory board reviews and approves populations, the database will be updated. Note that Family Tree DNA has strict requirements. Thus, not all published populations may be fit for inclusion.

    Continental Group Subcontinental Group Representative Population
    Africa
      Central African
        Biaka Pygmy
        Mbuti Pygmy
      East African
        Bantu [Kenya]
      Southern African
        Bantu [South Africa]
        San
      West African
        Mandenka
        Yoruba
    America
      Central American
        Maya
        Pima
      South American
        Columbian
        Karitiana
        Surui
    East Asia
      East Asian
        She
      East Central Asian
        Han
        Han [North China]
        Tujia
      Japanese
        Japanese
      Mongolian/Northeast Asian
        Daur
        Mongolian
        Oroqen
      Northeast Asian
        Hezhen
      Siberian
        Yakut
      South Central Chinese
        Naxi
      Southeast Asian
        Cambodian
        Dai
        Lahu
        Malay
        Miao
        Yi
    Europe
      Northeast European
        Finnish
        Russian
      Southeast European
        Romanian
      Southern European
        Italian
        Sardinian
        Tuscan
      Western European
        Basque
        French
        Orcadian (Orkney Islands)
        Spanish
    Middle Eastern
      Bedouin
        Bedouin
        Bedouin [South]
      Caucasus

    		  Adygei
      Iranian
        Iranian
      Jewish
        Jewish
      Middle Eastern
        Druze
        Palestinian
      North African
        Mozabite
    Oceania
      Melanesian
        Melanesian
      New Guinea
        Papuan
    South Asia
      Central Asian
        Hazara
        Tu
        Uygur
        Xibo
      Indian
        North Indian
        Southeast Indian
      Pakistani
        Balochi
        Brahui
        Burusho
        Kalash
        Makrani
        Pathan (Pashtun)
        Sindhi

  3. What is the source of the reference populations? faq id: 1040

    Many populations used by the Population Finder tool are from the work of the Human Genetic Diversity Project at the University of Stanford. Other population data from published academic work has been added. Below is a list of source papers that document the populations used.

    Reference:

    • Behar, D. M. et al (2010, June). The genome-wide structure of the jewish people. Nature  466 (7303), 238-242.
    • Cann, H. M. et al (2002, April). A human genome diversity cell line panel. Science (New York, N.Y.)  296 (5566), 261-262.
    • Rosenberg, N. A. et al (2002, December). Genetic structure of human populations. Science  298 (5602), 2381-2385.
    • Rosenberg, N. A. et al (2005, December). Clines, clusters, and the effect of study design on the inference of human population structure. PLoS Genet  1 (6), e70+
    • Teo, Y.-Y. et al (2009, November). Singapore genome variation project: A haplotype map of three southeast asian populations. Genome Research  19 (11), 2154-2162.

  4. Does the program use other customers’ data in comparisons? faq id: 1041

    No, data from other customers is not used. The data for the Population Finder tool comes from academic samples.

  5. Can I use the Population Finder tool to prove a family tradition? That is, will Population Finder tell me if I’m Jewish, Native America, etc.? faq id: 1042

    The Population Finder tool will often be able to detect ancestry from groups such as Jewish and Native American.

    However, it should not be used to disprove a family tradition. It is possible that you have an ancestor with which you do not share a detectable amount of genetic ancestry.

    See also: How many generations in the past can the Population Finder detect? and How many generations in the past do Population Finder results reflect?

  6. How many autosomal SNPs does the Population Finder tool use? faq id: 1046

    Population Finder uses about 295K out of 710K of the autosomal DNA SNPs (Single Nucleotide Polymorphisms) from the Family Finder microarray chip.

  7. How does Population Finder determine the percentages of different ancestries? faq id: 1049

    Population Finder determines the percentages of different ancestries that comprise your genetics by matching your autosomal DNA against a multi-dimensional data table (a matrix). In a multi-step process, the program finds the most likely combination of contributing population groups and the amount (percentage) of each. These are the basic steps.

    1. Your sample is processed by the Population Finder program. It is compared to each reference sample in our world DNA population database (see FAQ #1039 for current populations).
    2. A smaller data table is created using your sample and one representative population for each of the seven Continental groups. The populations represent the ancestral populations for each group.
      Ancestral Population Representative Population
      Middle East/North Africa Druze
      India North Indian
      Melanesian Melanesian
      Central America Pima
      Western Europe Orcadian (Orkney Islands)
      East Central Asia Tujia
      West Africa Yoruba

    3. The best matching ancestral population from step 2 is used to determine which of the reference populations will be most fully searched.
    4. The program searches the complete data table. It finds the best number of source populations to use (1 to 4).
    5. Where there are two or more populations from the same Subcontinental group, the ratio between them is reported.

  8. How many ancestral populations does the Population Finder tool show? faq id: 1050

    Based on your genetics, the Population Finder tool assigns your sample to Continental groups (from 1 to 4) and determines the percentages of each. It also designates the Subcontinental group where possible.

    The Population Finder program sets the number of groups shown. The program's choice is dependent on how many groups it determines are needed.

  9. How do you decide how many populations to show? faq id: 1051

    During the matching process, the program calculates the number of Continental and Subcontinental groups to show.

    Unless someone has a clear match to a single Continental group, the program will include a second Continental group. The program uses third and fourth groups only when they provide a significant improvement in the overall quality of the match.

  10. What is the population survey? Why am I being asked to fill it out? faq id: 1052

    The population survey is a tool that uses your feedback to determine which of a historically related set of population groups you best match. It is shown if you belong to a subset of populations that share common genetic ancestry. Because they are historically related, it is difficult to distinguish between them. In the current BETA release of Population finder, this happens in less than 00.5% of cases.

    In the survey, you are asked to choose the population group with which you most identify. Using this prior knowledge greatly reduces the margin of error.

    For example, you might be asked to select from Middle Eastern, Middle Eastern/North African, and None of the Above. You should choose the option that fits your knowledge of your ancestry. If you are adopted, do not know your ancestry, or none of the options seems right to you, you should select None of the Above.

  11. Does the Population Finder program use DNA segments the way Family Finder does? Does it use individual SNPs? faq id: 1053

    The Population Finder program compares each autosomal DNA Single Nucleotide Polymorphism (SNP) individually. It does not use linked DNA segments.

  12. Does the Population Finder tool use non-autosomal DNA results? faq id: 1054

    No, only your autosomal DNA results from the Family Finder microarray chip are used. The Population Finder tool does not use Mitochondrial DNA (mtdna), X-chromosome DNA, or Y-chromosome DNA results.

  13. How many generations in the past do Population Finder results reflect? faq id: 1166

    Population Finder results are your personal genetic ancestry that reflects the last 100 to 2,000 years (about 4 to 80 generations). They may also reflect one population that mixed with another in ancient times and became fixed in the second population.

    See also: How many generations in the past can the Population Finder detect? and Does the Population Finder program use DNA segments the way Family Finder does?

  14. Why have my results changed? faq id: 1167

    Your results have changed because we have updated the Family Tree DNA world population database and the Family Finder program. When we update them, all customers' results are also updated.

  15. Some of my relatives have results that show both a larger group and a subset in parenthesis. Others only show the larger group. What is the difference? faq id: 1168

    If only the larger (Continental) group shows, during the matching process the person matched populations from more than one Subcontinental group within the Continental group. When the matching populations are all from the same Subcontinental group, the Subcontinental group is shown in parenthesis beside the Continental group.

    For example, Ed TIPTOP has the following results.

    Illumina OmniExpress Results
    Continent (Subcontinent) Population Percentage Margin of Error
    Europe (Western European) French, Orcadian 52.38% +/-0.01%
    America Columbian, Pima 47.62% +/-0.01%

    Europe (Western European) is shown because Ed matched both the French and Orcadian (Orkney Islands) populations.

    America is shown because Ed matched the Pima population in the Central American Subcontinental group and the Columbian population in the South American Subcontinental group.

  16. My results show two different populations. One seems to be a subset of the other. Why is this? faq id: 1169

    Your results show that you have genetic ancestry from more than one region within the same Continental group. This happens most often when you are a strong match to one group for the majority of your ancestry, but there is a clear contribution from another group or groups.

    For example, Nora NEEFLY has these results.

    Illumina OmniExpress Results
    Continent (Subcontinent) Population Percentage Margin of Error
    Europe (Western European) Orcadian 93.27% +/-2.38%
    Europe Finnish, Romanian 6.73% +/-2.38%

    Her results show Europe (Western European) for her first contributing group. This is because she had a strong match with the Orcadian (Orkney Islands) population.

    She shows Europe for her second contributing group. This is because the remainder of her ancestry matched the Finnish population from the Northeast European Subcontinental group and the Romanian population from the Southeast European Subcontinental group.

  17. How can I tell which side of my family (mother or father) a population match comes from? faq id: 1173

    It is not possible to tell how much of each region you match is from each parent. This is because your autosomal DNA comes equally but randomly from each parent.

  18. Can the Population Finder tool determine the specific country from which my ancestors originated? faq id: 1174

    No, strict political boundaries (ancient or current) do not set variance in human genetics. There has always be been movement between geographic regions. The result is gradients in the frequencies of each genetic marker. 

  19. The tool says 35% of my ancestry comes from the Southern Europe region. What does that tell me in terms of my shorter term ancestry vs. longer term ancestry? faq id: 1175

    Your percentage from any one reference population may reflect either recent or long term genetic ancestry. Determining which it is requires that you evaluate your results in light of what you know of your family history and the history of your ancestors.

    Having about one third of your ancestry from a population may indicate that there has been recent admixture in your family. That is, some of your recent ancestors were from that population.

    On the other hand, it may indicate that some ancestors migrated from the location of the reference population and lived in their new location for many generations. Thus, the admixture levels are common to all from the town's population.

    See also: How many generations in the past can the Population Finder detect? and How many generations in the past do Population Finder results reflect?

  20. This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working? faq id: 1176

    Human history (and anthropology) is more complex than the bounds of a single country of origin. Genetic ancestry is most often a gradual transition in the frequencies of different variants. Over the past 2,000 to 3,000 years, there has also been frequent admixture between populations.

    There are exceptions such as the Basques and Sardinians, but these are outstanding exceptions. The human race generally shows our single common origin. Therefore, a European might not have a strictly European genome. Nor should any single population group expect to be exclusive of all others.

    The program selects reference populations that best match your genetics. However, your ancestry may trace to a related population that is not represented in the comparison database.

    For example, Lenora DIDMOW has some ancestry from western Sicily. The rest is from the United Kingdom. She has the following Population Finder results.

    Illumina OmniExpress Results
    Continent (Subcontinent) Population Percentage Margin of Error
    Europe French, Orcadian 95.46% +/-2.32%
    South Asia South Indian, North Indian 4.54% +/-2.32%

    Her South Asian ancestry may be due to the history of and population settlements in parts of Sicily or the limitations of the available reference populations.

    See also: Can the Population Finder tool determine the specific country from which my ancestors originated? and My results include a list of countries. Is my ancestry from all of these countries? Is it always from one of them?

  21. In the Population Finder program's analysis, are there any regions or populations that are particularly hard to tell apart? faq id: 1177

    How difficult it is to tell apart two populations depends on whether or not the populations in question share recent histories (one hundred to two thousand years). When they do, it is much harder to distinguish between them.

    One such situation is for people from Southern Europe (Italy, Greece, etc.) and the Middle East (Jewish populations, Palestinians, etc.). Historically, there have been population movements between Southern Europe and the Middle East. These have been in the form of trade, enslavements, and forced religious conversions. As a result, people with known genealogical ancestry from one group may show genetic ancestry from the other.

    In these cases, Population Finder program results reflect the genetic ancestry. For example, someone who is one half Southern Italian might have these results.

    Illumina OmniExpress Results
    Continent (Subcontinent) Population Percentage Margin of Error
    Europe French 52.15% +/-2.39%
    Middle East Adygei, Druze, Iranian, Jewish 47.85% +/-2.39%

  22. My results include a list of countries. Is my ancestry from all of these countries? Is it always from one of them? faq id: 1178

    The countries shown in your Population Finder results and on the Population Finder map correspond to the program's reference populations (see FAQ #1039). Your actual heritage may come from one of those countries, two or more countries that are equidistant from those countries, or several of those countries. This is because genetic variation is a gradient between any two locations.

    For example, if your actual ancestry is from Germany, but the program uses a mixture of Orcadian (Orkney Islands) and South Indian samples to create the same genetic combination.

    See also: What is the Population Finder page?, On the Population Finder page, what are the maps?, Can the Population Finder tool determine the specific country from which my ancestors originated?, I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working?

  23. Is the percentage an admixture amount or a match probability? faq id: 1184

    The percentages provided by Population Finder are admixture amounts.

    A program that calculates admixture amounts uses the DNA profiles from multiple regions and populations to discover a combination that fits with your genetic profile. It reports the amount of each population used to obtain a high quality match. This is able to identify correctly when someone has ancestry from more than one population or region, as most of us do.

    On the other hand, a program that assesses a match probability tries to match you to a single population. It rates the match quality with a likelihood number. Results give the likelihood number as a percentage. This type of calculation only works well when the person tested is from one and only one population. That population also needs to be included in the comparison database.

  24. Why don't the percentages from each population add up to 100%? faq id: 1185

    Your results may not add up to 100% if you have a small amount of DNA that matches a population. The Population Finder program does not report a match when it is too distant to report with confidence. This ensures the quality of your matches, but, as a result, the total percentage from the other populations that you match may be less than 100%.

  25. What is the Margin of Error? How is it determined? faq id: 1186

    The Population Finder program locates several possible sets of populations that match your genetic ancestry. The Margin of Error indicates how much the matching percentage from a given region varies among these possible matches.

    For example, if part of your matching is to Western European French, Orcadian, and Spanish reference populations, the matches respectively might be 90%, 95%, and 85%. The Margin of Error is the measurement of how the three percentages vary.

  26. What is the impact of the Margin of Error on the conclusions I can draw? faq id: 1187

    You should use the margin of error to consider how much more or less of ancestry from a population you may have. For example, if the percentage from a region is 50% and the margin of error is 2.5% then you might have as much as 52.5% of your genetic ancestry from that region or as little as 47.5%.

  27. What does it mean if the Margin of Error is very high? faq id: 1188

    A high Margin of Error means that you match two or more sets (pairs, triples, or quadruples) of similar populations. Because the Population Finder program cannot distinguish between them clearly, it reports your match to each population with a high Margin of Error, for example, +/-15%.

    See also: In the Population Finder program's analysis, are there any regions or populations that are particularly difficult to distinguish?

  28. I have a family tradition of Native American ancestry. Is the Population Finder tool able to detect it? faq id: 1204

    The Population Finder program can detect a significant Native American contribution to your genetic ancestry. If you have a 100% genetically pre-Colombian ancestor in your recent genealogy, Population Finder is highly likely to detect it.

    Generation Relationship Percentage
    1 Self 100.00%
    2 Parent 50.00%
    3 Grandparent 25.00%
    4 1st Great Grandparent 12.50%
    5 2nd Great Grandparent 6.25%
    6 3rd Great Grandparent 3.13%
    7 4th Great Grandparent 1.56%

    For example, if your great-grandmother was 100% pre-Colombian Native America, Population Finder will detect your approximately 12.5% Native American ancestry.

    Population Finder is also likely to detect Native American ancestry that is a high percentage of a modern population. As another example, if you have all four grandparents with Native American ancestry from Mexico, your Population Finder results will reflect the amount of pre-Colombian ancestry that is within a normal range for those with Mexican heritage.

    However, in the current release, the available reference populations limit the ability of the program to identify your specific ancestral group. It may also under detect heritage that comes from a distinctive un-represented group such as the Na-Dene.

    Continental Group Subcontinental Group Representative Population
    America
      Central American
        Maya
        Pima
      South American
        Columbian
        Karitiana
        Surui

    Remember that you may have a Native American ancestor but not have sufficient genetic heritage from them to be detected by a DNA test. This is due to the randomness of autosomal recombination.

    Therefore, genetic testing can confirm your ancestry but not disprove it.

    See also: What reference populations are used?

  29. I would like to prove a family tradition. How many generations in the past can the Population Finder detect? faq id: 1205

    The Population Finder tool can detect small traces of genetic ancestry as low as 3% (about 5 to 6 generations) from a distinct Continental group. This is most true where there has been little admixture.

    Generation Relationship Percentage
    1 Self 100.00%
    2 Parent 50.00%
    3 Grandparent 25.00%
    4 1st Great Grandparent 12.50%
    5 2nd Great Grandparent 6.25%
    6 3rd Great Grandparent 3.13%
    7 4th Great Grandparent 1.56%

    For example, someone might have one 2nd grandmother from Africa. Their other fifteen 2nd great grandparents may be from European countries. The Population Finder program is likely to detect the African 2nd great grandmother's ancestry.

    Where the populations are from the same Subcontinental group or there has been admixture, it is less sure that the program will detect any one ancestor in the 5th or 6th generation.

    For example, someone might have mixed ancestry from Finland. Fourteen of their 2nd great grandparents have Finish ancestry while the other two have Russian ancestry. It is unlikely that Population Finder will distinguish between these populations.

    See also: How many generations in the past do Population Finder results reflect? and Does the Population Finder program use DNA segments the way Family Finder does?

  30. All of my genealogy comes from Europe. Why do my Population Finder results include Africa? faq id: 1208

    If you have a known European genealogy and partial genetic ancestry from Africa, it indicates that some of your ancestry traces to Africa or perhaps North Africa. It is important to note that North Africa is considered part of the Middle Eastern Continental group, but there is a gradient of genetic similarity between African and North African populations. Your genetic ancestry may be from ancestors who were taken to Europe and the Americas as indentured servants and slaves.

    At times, the source may first trace back to those who intermarried with Native Americans.

    When considering what genetic ancestry from Africa means to you and your research, you should consult the full list of reference populations for the African Continental group and each of its Subcontinental groups.

    See also: What reference populations are used?, This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working?, and How many generations in the past do Population Finder results reflect?

  31. All of my genealogy comes from Europe. Why do my Population Finder results include America? faq id: 1209

    The most likely reason for someone with a European genealogy to have genetic ancestry from the Americas is a previously unknown Native American ancestor. This may be from North or South America. In some cases, the source may include people who were taken to Europe by European explorers during the early years of European Colonization.

    When considering what genetic ancestry from America means to you and your research, you should consult the full list of reference populations for the America Continental group and each of its Subcontinental groups.

    See also: What reference populations are used?, This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working?, and How many generations in the past do Population Finder results reflect?

  32. All of my genealogy comes from Europe. Why do my Population Finder results include East Asia? faq id: 1210

    For someone with Eastern European ancestry, some genetic ancestry from East Asia is expected due to historic population expansions from the East.

    When considering what genetic ancestry from East Asia means to you and your research, you should consult the full list of reference populations for the East Asia Continental group and each of its Subcontinental groups.

    See also: What reference populations are used?, This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working?, and How many generations in the past do Population Finder results reflect?

  33. All of my genealogy comes from Europe. Why do my Population Finder results include Middle East? faq id: 1211

    There have been many migrations between Europe and the Middle East including those of early Neolithic farmers. Thus, there are also many reasons for someone from Europe to have a small amount of Middle Eastern genetic ancestry.

    Anyone from a Mediterranean country or other European border country will also have genetic ancestry that has much in common with the Middle East. This makes it difficult to distinguish between them.

    When considering what genetic ancestry from Middle East means to you and your research, you should consult the full list of reference populations for the Middle East Continental group and each of its Subcontinental groups.

    See also: What reference populations are used?, This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working?, and How many generations in the past do Population Finder results reflect?

  34. All of my genealogy comes from Europe. Why do my Population Finder results include South Asia? faq id: 1213

    When you have European ancestry and some South Asian genetic ancestry, it is highly likely that the source population comes from a group like the Rom and Sinti peoples.

    When considering what genetic ancestry from South Asia means to you and your research, you should consult the full list of reference populations for the South Asia Continental group and each of its Subcontinental groups.

    See also: What reference populations are used?, This test says that I have some ancestry from a specific region. I know that all of my ancestors were from a different population(s). Could the Population Finder be wrong? Is it not working?, and How many generations in the past do Population Finder results reflect?

  35. I had my Family Finder results analyzed using a third party service. Why do the results differ from Population Finder? faq id: 1668

    If you use a third party tool, it is natural for there to be minor differences for the Population Finder Beta due to either different methodologies or different population sets.