Glossary

  1. Aboriginal faq id: 637
  2. Adenine faq id: 638
  3. Administrator faq id: 639
  4. Admixture faq id: 640
  5. Allele faq id: 641
  6. American Indian faq id: 642
  7. Amplification faq id: 643
  8. Ancestor faq id: 644
  9. Ancestral haplotype faq id: 645
  10. Ancestral Signature faq id: 646
  11. Ancestral State faq id: 647
  12. Anthrogenealogy faq id: 648
  13. Anthropology faq id: 649
  14. Ashkenazi faq id: 650
  15. Atlantic Modal Haplotype (AMH) faq id: 651
  16. Autosomal DNA (atDNA) faq id: 652
  17. Back Mutation faq id: 654
  18. Base faq id: 656
  19. Base Pair faq id: 657
  20. Biogeographical Analysis faq id: 659
  21. Buccal Cell faq id: 660
  22. Cambridge Reference Sequence (CRS) faq id: 661
  23. Catalyst faq id: 662
  24. centiMorgan (cM) faq id: 663
  25. Centromere faq id: 664
  26. Chromatid faq id: 666
  27. Chromosome faq id: 667
  28. Clade faq id: 668
  29. Coding Region faq id: 669
  30. Cohanim Modal Haplotype (CMH) faq id: 670
  31. Cohen faq id: 671
  32. Combined DNA Index System (CODIS) faq id: 672
  33. Complementary Sequences faq id: 673
  34. Convergence faq id: 674
  35. Cross-over faq id: 675
  36. Cytosine faq id: 676
  37. Deletion faq id: 677
  38. Deoxyribonucleic acid (DNA) faq id: 678
  39. Derived State faq id: 679
  40. Descendant faq id: 680
  41. Diaspora faq id: 681
  42. DNA Amplification faq id: 682
  43. DNA Replication faq id: 683
  44. DNA Segment faq id: 684
  45. DNA Sequencing faq id: 685
  46. Double Helix faq id: 687
  47. Endogamous faq id: 688
  48. Enzyme faq id: 689
  49. Exact match faq id: 691
  50. Exogamy faq id: 692
  51. Factoid faq id: 693
  52. Family Tree DNA Time Predictor (FTDNATiP TM) faq id: 694
  53. Gene faq id: 695
  54. Genealogical Time-frame faq id: 696
  55. Genealogical Data Communication (GEDCOM) faq id: 697
  56. Genealogy faq id: 698
  57. Generation faq id: 699
  58. Genetic Cousins faq id: 700
  59. Genetic Distance faq id: 701
  60. Genetic Drift faq id: 702
  61. Genetic Genealogy faq id: 703
  62. Genetics faq id: 704
  63. Genome faq id: 705
  64. Genotype faq id: 706
  65. Glacial Maximum faq id: 707
  66. Group Administrator Page (GAP) faq id: 708
  67. Guanine faq id: 709
  68. Half Identical Region (HIR) faq id: 710
  69. Haplogroup faq id: 711
  70. Haplotype faq id: 712
  71. Heredity faq id: 714
  72. Heterozygous faq id: 715
  73. Homozygous faq id: 716
  74. Human Genome Organization (HUGO) faq id: 718
  75. Hypervariable Region (HVR) faq id: 719
  76. Identical By Descent (IBD) faq id: 720
  77. Identical By State (IBS) faq id: 721
  78. Inbreed faq id: 722
  79. Indel faq id: 723
  80. Insertion faq id: 724
  81. Israelite faq id: 725
  82. Junk DNA faq id: 726
  83. Levite faq id: 727
  84. Lineage faq id: 728
  85. Locus faq id: 729
  86. Marker faq id: 730
  87. Meiosis faq id: 732
  88. Micro-Allele faq id: 733
  89. Microarray Chip faq id: 734
  90. Microsatellite faq id: 735
  91. Mitochondria faq id: 736
  92. Mitochondrial DNA (mtDNA) faq id: 737
  93. Mizrahi faq id: 738
  94. Modal Haplotype faq id: 739
  95. Most Recent Common Ancestor (MRCA) faq id: 740
  96. Mutation faq id: 742
  97. Mutation rate faq id: 743
  98. myFTDNA faq id: 744
  99. Non-coding DNA faq id: 747
  100. Non-Recombining Y (NRY) faq id: 748
  101. Nuclear DNA faq id: 749
  102. Nucleic Acids faq id: 750
  103. Nucleoside faq id: 751
  104. Nucleotide faq id: 752
  105. Nucleus faq id: 753
  106. Null faq id: 754
  107. Organelle faq id: 755
  108. Outbreed faq id: 756
  109. P Arm faq id: 757
  110. Palindrome faq id: 758
  111. Parallel Mutation faq id: 759
  112. Pherogram faq id: 760
  113. Phylogenetics faq id: 761
  114. Phylogenetic tree faq id: 762
  115. Polymerase faq id: 763
  116. Polymerase Chain Reaction (PCR) faq id: 764
  117. Polymorphism faq id: 765
  118. Population faq id: 766
  119. Population Bottleneck faq id: 767
  120. Primer faq id: 768
  121. Protein faq id: 769
  122. Principal Component Analysis (PCA) faq id: 770
  123. Recombinational Loss of Heterozygosity (recLOH) faq id: 772
  124. Recombination faq id: 773
  125. Replication faq id: 774
  126. Restriction Enzyme faq id: 775
  127. Restriction Fragment Length Polymorphism (RFLP) faq id: 776
  128. Sephardic faq id: 778
  129. Sequencing faq id: 779
  130. Sex Chromosome faq id: 780
  131. Short Tandem Repeat (STR) faq id: 781
  132. Single Nucleotide Polymorphism (SNP) faq id: 782
  133. Sister clade faq id: 783
  134. Subclade faq id: 784
  135. Surname faq id: 785
  136. Telomere faq id: 786
  137. Thymine faq id: 787
  138. Time to the Most Recent Common Ancestor (TMRCA) faq id: 788
  139. Transition faq id: 790
  140. Transmission Event faq id: 791
  141. Transversion faq id: 792
  142. Unique Event Polymorphism (UEP) faq id: 793
  143. Western Atlantic Modal Haplotype (WAMH) faq id: 794
  144. X-chromosome faq id: 795
  145. Y-chromosome faq id: 796
  146. Y-chromosome Consortium (YCC) Tree faq id: 797
  147. Most Distant Known Ancestor (MDKA) faq id: 1677
  148. Most Distant Known Origin (MDKO) faq id: 1678
  149. RSRS (Reconstructed Sapiens Reference Sequence) faq id: 2089

Questions and Answers

  1. Aboriginal faq id: 637

    Aboriginal means relating to a group of people native to a geographic region. These are the original inhabitants of a region.

  2. Adenine faq id: 638

    Adenine is one of the four bases that make up our DNA. It is abbreviated "A."

    The other bases are thymine (T), guanine (G) and cytosine (C). Adenine always pairs with thymine.

  3. Administrator faq id: 639

    An administrator is someone who is in charge. The group projects at Family Tree DNA are run by unpaid volunteer administrators.

  4. Admixture faq id: 640

    Admixture refers to ancestry from more than one recent population group. Many people today have ancestry from more than one population and/or location.

  5. Allele faq id: 641

    An allele is a genetic variant at a locus, a specific location, in our genetic code.

  6. American Indian faq id: 642

    American Indian is the popular term for the Indigenous Peoples of the Americas. These are the descendants of the early settlers in North and South America.

  7. Amplification faq id: 643
  8. Ancestor faq id: 644

    An ancestor is someone from which you descend. For example, your grandparents are your ancestors.

  9. Ancestral haplotype faq id: 645

    In genetic genealogy, the ancestral haplotype is the set of marker values of your ancestor.

  10. Ancestral Signature faq id: 646

    The ancestral signature is the oldest known or suspected haplotype for a lineage.

    See also: Modal Haplotype

  11. Ancestral State faq id: 647

    In genetic genealogy, the ancestral state is the marker value that your ancestor had.

  12. Anthrogenealogy faq id: 648

    Anthrogenealogy is the study of human origins, recent and distant, using DNA testing and genealogy.

  13. Anthropology faq id: 649

    Anthropology is the study of human origins and culture.

  14. Ashkenazi faq id: 650

    Ashkenazi is the branch of the Jewish population that settled in Germany and then Eastern Europe during the Jewish Diaspora.

  15. Atlantic Modal Haplotype (AMH) faq id: 651
  16. Autosomal DNA (atDNA) faq id: 652

    Autosomal DNA is DNA from one of our chromosomes located in the cell nucleus. It generally excludes the sex chromosomes. Humans have 22 pairs of autosomal chromosomes and a pair of sex chromosomes.

    Source: "autosome". Oxford Dictionaries. April 2010. Oxford Dictionaries. April 2010. Oxford University Press. 09 February 2013 (http://oxforddictionaries.com/definition/english/autosome?q=autosome)

  17. Back Mutation faq id: 654

    A Back Mutation is when a marker value changes back to its original value.

  18. Base faq id: 656

    A base is a unit or building block of DNA. Adenine (A), cytosine (C), guanine, (G), and thymine (T) are the four primary bases in DNA. The order of bases is the sequence of DNA.

  19. Base Pair faq id: 657

    In genetics, nucleotides are called bases. A base pair (bp) is two complementary nucleotides on opposite strands of DNA. Base pairs are measured using metric units.

    • 1 base pair = 1 base pair (bp)
    • 1,000 base pairs = 1 kilo-base (kb)
    • 1,000,000 base pairs = 1 mega base (Mb)

  20. Biogeographical Analysis faq id: 659

    Biogeographical Analysis it the study of how an organism varies genetically with respect to its geographic location.

    In genetic genealogy, we are all part of the human race. For us, biogeographical analysis refers to analyzing the differences that have developed between population groups. These are small changes that have happened since our common ancestors migrated from Africa.

  21. Buccal Cell faq id: 660

    A buccal cell is a type of cell found in cheek tissue inside the mouth.

  22. Cambridge Reference Sequence (CRS) faq id: 661

    The Cambridge Reference Sequence (CRS) is the mitochondrial DNA sequence first sequenced in 1981. It was used as a basis for comparison with mtDNA test results until it was replaced with the RSRS (Reconstructed Sapiens Reference Sequence).

  23. Catalyst faq id: 662

    A catalyst is a substance which starts or speeds up a chemical reaction without being affected by that reaction.

  24. centiMorgan (cM) faq id: 663

    A centiMorgan (cM) is a measurement of how likely a segment of DNA is to recombine from one generation to the next. A single centiMorgan is considered equivalent to a 1% (1/100) chance that a segment of DNA will crossover or recombine within one generation.

    For humans, one million base pairs (bp) average about one centiMorgan. However, the rate of recombination is highly variable.

  25. Centromere faq id: 664

    A centromere is one of the parts of each chromosome. It is a dense area that joins together the two chromatids (arms) of each chromosome.

  26. Chromatid faq id: 666

    A chromatid is one of two strands of a chromosome.

  27. Chromosome faq id: 667

    A chromosome is a structure found in the nucleus of a cell that contains genetic material. Humans have 23 pairs of chromosomes, 22 pairs of autosomes and one pair of sex chromosomes.

  28. Clade faq id: 668

    A clade is a group of related individuals.

  29. Coding Region faq id: 669

    A coding region is DNA which contains genes. In genetic genealogy, this most often refers to the part of the mitochondrial genome that contains genes.

  30. Cohanim Modal Haplotype (CMH) faq id: 670

    The Cohanim Modal Haplotype (CMH) is the Y-chromosome (paternal) profile most frequently found in men with an oral tradition of Cohen ancestry. It is a Y-chromosome DNA STR (Short Tandem Repeat) haplotype.

  31. Cohen faq id: 671

    Cohen is the Hebrew word for priest which refers to a direct male descendant of Aaron, the brother of Moses. The plural is Cohanim.

  32. Combined DNA Index System (CODIS) faq id: 672

    The CODIS system uses marker locations in the autosomal DNA. In the United States, the FBI maintains a CODIS test result database to identify people and solve crimes.

  33. Complementary Sequences faq id: 673

    Complementary Sequences are opposing strands of DNA. They bond together to form the double helix. The bases always complement one another. Adenine and Thymine pair together. Cytosine and Guanine pairing together.

  34. Convergence faq id: 674

    Convergence is the process of two genetically distant haplotypes changing over time to resemble one another.

  35. Cross-over faq id: 675
  36. Cytosine faq id: 676

    Cytosine is the "C" of the four bases that make up DNA. Cytosine always pairs with guanine.

    The other bases are adenine (A), guanine (G), and thymine (T).

  37. Deletion faq id: 677

    A deletion is when on or more of the letters (nucleotides) of your genetic code is deleted.

  38. Deoxyribonucleic acid (DNA) faq id: 678

    DNA, Deoxyribonucleic acid, is the genetic code that makes each of us a unique individual. Humans inherit about one half of their genetic code from each of their parents. Our genetic code then holds the story of our heritage that has been passed down through the generations.

  39. Derived State faq id: 679

    The derived state of a mutation is when someone possesses the mutation.

  40. Descendant faq id: 680

    A descendant is someone who descends from a specific ancestor. For example, your children and grandchildren are your descendants.

  41. Diaspora faq id: 681

    A diaspora is the permanent displacement of a population from one location to a different location or locations.

  42. DNA Amplification faq id: 682

    DNA Amplification is the production of many DNA copies from one or a few copies or fragments.

  43. DNA Replication faq id: 683

    DNA replication is the process by which the DNA double helix makes a copy of itself. It uses the old DNA as a template for the synthesis of new DNA strands. In humans, replication occurs in the cell nucleus.

  44. DNA Segment faq id: 684

    A DNA segment is any continuous run or length of DNA. It is described by the locus where it starts and the locus where it stops.

  45. DNA Sequencing faq id: 685

    DNA Sequencing is the process of determining the exact order of the nucleotide bases in a segment of DNA.

  46. Double Helix faq id: 687

    A double helix is the twisted shape DNA forms when its two strands bond together. It looks like a twisting or rotating ladder.

  47. Endogamous faq id: 688

    An endogamous population is one where the members usually only marry within the population group. The bases for endogamy may be geography, ethnic identity, social class, or religion. Long periods of intermarriage have left many endogamous populations with lower than average levels of genetic diversity. Examples of historically endogamous populations are the Amish, the Basque, and the various subpopulations of the Jewish Diaspora.

  48. Enzyme faq id: 689

    A protein that facilitates a specific chemical reaction by working as a catalyst.

  49. Exact match faq id: 691

    An exact match is when two people have exactly the same results for all markers or regions compared.

  50. Exogamy faq id: 692

    Exogamy is marriage outside of a cultural or population group.

  51. Factoid faq id: 693

    A factoid is an unverified piece of information. In genetic genealogy, it refers to genetic findings that are over reported in popular culture. These factoids may have no validity.

  52. Family Tree DNA Time Predictor (FTDNATiP TM) faq id: 694

    Family Tree DNA Time Predictor (FTDNATiP TM) is a program used to calculate estimates of Time to Most Recent Common Ancestor (TMRCA). It is the world's first calculator that incorporates mutation rates specific to each marker. This increases the power and precision of estimates.

  53. Gene faq id: 695

    A Gene is a region of DNA which codes for a protein or part of a protein.

  54. Genealogical Time-frame faq id: 696

    The genealogical time frame is the most recent one to fifteen generations. Recent genealogical times are the last one to five generations.

  55. Genealogical Data Communication (GEDCOM) faq id: 697

    A Genealogical Data Communication (GEDCOM) file is a special file format that was developed to provide a standard for encoding genealogical data. It is not used by most family tree software packages but most can import and export to GEDCOM format. Because of this, it is today used by many genealogists to exchange pedigree data files.

  56. Genealogy faq id: 698

    Genealogy is the study of family history.

  57. Generation faq id: 699

    A generation is the number of years between the birth of the parents and the birth of their children. Different studies use different numbers of years per generation. At Family Tree DNA we use 25 years. However, for Time to Most Common Ancestor (TMCA) calculations, it is the number of generations that is important.

  58. Genetic Cousins faq id: 700

    Individuals whose DNA test results match one another.

  59. Genetic Distance faq id: 701

    There are two meanings of Genetic Distance.

    1. Genetic Distance is the number of differences, or mutations, between two sets of results. A genetic distance of zero means there are no differences in the results being compared against one another, i.e., an exact match. This is the meaning when comparing Y-chromosome DNA or mitochondrial DNA.
    2. For autosomal DNA comparisons, genetic distance may refer to the size of a DNA segment. The genetic distance is then the length of the segment in centiMorgans.

  60. Genetic Drift faq id: 702

    Genetic drift is when a subset of a population moves to a different location and becomes genetically less like the main population. This happens over many generations.

  61. Genetic Genealogy faq id: 703

    Genetic genealogy is the use of your DNA to solve genealogy puzzles.

  62. Genetics faq id: 704

    Genetics is the study of genes and heredity; the study of DNA.

  63. Genome faq id: 705

    A genome is the entire complement of an organism's genetic material. This may refer to the DNA of a gamete, organelles (mitochondria and chloroplasts), organism, or species.

    The human nuclear genome is composed of 46 chromosomes (23 pairs). They contain a total of 3 billion base pairs.

    The human mitochondrial genome is composed of a single circular DNA sequence that contains 16569 base pairs.

  64. Genotype faq id: 706

    The genetic makeup of an individual organism.

  65. Glacial Maximum faq id: 707

    Glacial Maximum is the scientific term for the peak of an ice age.

  66. Group Administrator Page (GAP) faq id: 708

    The Group Administrator Page (GAP) is the user interface that Family Tree DNA project administrators use to manage group projects. The term GAP is also often used for project administrators.

  67. Guanine faq id: 709

    Guanine is the "G" of the four bases that make up DNA. Guanine always pairs with cytosine.

    The other bases are adenine (A), cytosine (C), and thymine (T).

  68. Half Identical Region (HIR) faq id: 710

    A half identical region (HIR) is when two people's share a DNA segment that half matches. The half identical region may be either identical by descent (IBD) or identical by state (IBS).

    Note: This is a colloquialism.

  69. Haplogroup faq id: 711

    A haplogroup is a major branch on either the maternal or paternal tree of humankind. Haplogroups are associated with early human migrations. Today these can associated with a geographic region or regions.

    Note: Though maternal and paternal haplogroups may have similar naming systems, their definitions are different.

  70. Haplotype faq id: 712

    A haplotype is the set of values for a set of DNA values. For example, the results of the Y-DNA12 test for one person is their haplotype.

    Two individuals that match exactly on all markers have the same haplotype.

  71. Heredity faq id: 714

    Heredity is the transmission of genetic material from parents to offspring.

  72. Heterozygous faq id: 715

    Heterozygous means that the two allele values at a locus are different.

    AlleleHeterozygous Value
    A -A
    C -C
    G -G
    T -T
    A AG
    C CT

  73. Homozygous faq id: 716

    Homozygous means that both allele values at a locus are identical.

    AlleleHomozygous Value
    A AA
    C CC
    G GG
    T TT
    - --

  74. Human Genome Organization (HUGO) faq id: 718

    The Human Genome Organization (HUGO) is the scientific entity to which, among other things, researchers submit new Short Tandem Repeat (STR) markers for number assignment.

  75. Hypervariable Region (HVR) faq id: 719

    A hypervariable region (HVR) is a part of the mitochondrial genome. There are two human Hypervariable Regions. They do not contain genes. Therefore, they have a faster change (mutation) rate than the coding part of the mitochondrial genome.

  76. Identical By Descent (IBD) faq id: 720

    IBD stands for Identical By Descent. This means the DNA matches because it comes from a common ancestor. IBD can refer to a single mutation or to a segment of DNA. If a mutation or segment of DNA is IBD among a group of people, it comes from a common ancestor.

    The Family Finder relationship predictions require a minimum number of results in a row to be identical in order to identify that the segment is likely to be IBD.

  77. Identical By State (IBS) faq id: 721

    IBS stands for Identical By State, meaning the DNA matches by coincidence. When two individuals share numerous individual results without being related, those results are IBS.

  78. Inbreed faq id: 722

    In genetics, inbreed refers to someone whose parents are related. It most often refers to cases where the relationship is within five generations.

  79. Indel faq id: 723

    An indel is a type of mutation where genetic code is lost or gained. These are insertions and deletions.

  80. Insertion faq id: 724

    An insertion is when one or more the letters (nucleotides) of genetic code is added.

  81. Israelite faq id: 725

    A descendant of the Hebrew tribes.

  82. Junk DNA faq id: 726

    Junk DNA is a popular term for DNA that does not contain genes. This is non-coding DNA. Most of the genome consists of non-coding DNA. Because it does not code for specific function, it was long thought to be 'junk.' However, scientists have found that in addition to containing markers that are helpful for genetic genealogy, parts of these non-coding regions have regulatory and other functions.

  83. Levite faq id: 727

    A descendant of the Hebrew tribe of Levi. There are strict historic guidelines for who is considered a Levite.

  84. Lineage faq id: 728

    A lineage is all descendants of a specific ancestor.

  85. Locus faq id: 729

    A locus is a specific location in your genetic code. In a genetic map of our DNA the locus tells us where to find any base. Each locus is named sequentially so that on chromosome 15 locus 26039212 comes after locus 26039211. The plural of locus is loci.

  86. Marker faq id: 730

    A marker is a physical location (locus) on the chromosome. The term is often used colloquially in genetic genealogy to refer to a short tandem repeat (STR). For example, "The Y-DNA67 test is a panel of 67 markers."

    See also: Locus, Short Tandem Repeat (STR)

  87. Meiosis faq id: 732

    The stage in the reproductive process in which sperm and egg cells are formed. During meiosis the autosomal chromosomes recombine and mutations may occur.

  88. Micro-Allele faq id: 733

    A micro-allele is when part of a repeat for an STR (short tandem repeat) is lost. 

  89. Microarray Chip faq id: 734

    A microarray or SNP Chip is a high density DNA test that is able to test many thousands of single nucleotide polymorphisms (SNPs) at once. The microarray chip is able to capture much of the diversity in someone's genetic code by sampling known polymorphic loci.

  90. Microsatellite faq id: 735
  91. Mitochondria faq id: 736

    A specific organelle in the cell that helps it to produce energy.

  92. Mitochondrial DNA (mtDNA) faq id: 737

    The genetic material found in mitochondria. It is passed down from females to both sons and daughters, but sons do not pass down their mother's mtDNA to their children.

  93. Mizrahi faq id: 738

    Mizrahi is the branch of the Jewish population that settled in Middle Eastern, North Africa, Caucasus countries. This may include Sephardi Jews who move to these places.

  94. Modal Haplotype faq id: 739

    The most common result for each marker tested in a group of results.

    See also: Ancestral Signature

  95. Most Recent Common Ancestor (MRCA) faq id: 740

    The ancestor shared most recently between two individuals.

  96. Mutation faq id: 742

    A heritable change that occurs in genetic material. It may lead to a different number of repeats of a certain sequence or a change in one of the bases in a sequence.

  97. Mutation rate faq id: 743

    The frequency with which random mutations occur.

  98. myFTDNA faq id: 744

    myFTDNA is the user interface that Family Tree DNA customers use to view their test results and matches.

  99. Non-coding DNA faq id: 747

    Non-coding DNA is DNA that does not contain genes. It may have other functions.

  100. Non-Recombining Y (NRY) faq id: 748

    The non-recombining Y (NRY) is the part of the Y-chromosome that does not recombine with the X-chromosome.

  101. Nuclear DNA faq id: 749

    Nuclear DNA is the genetic code that is found inside of the cell's nucleus. Our autosomal and sex chromosomes are nuclear DNA.

  102. Nucleic Acids faq id: 750

    Nucleic acids are the basic components of our genetic code. DNA is made up of four types of nucleic acids: adenine (A), cytosine (C), guanine (G), and thymine (T).

  103. Nucleoside faq id: 751

    Nucleosides are structural components of our genetic code. Each of the four nucleic acids in our DNA bonds with a sugar to form four nucleosides: Adenosine, Cytidine, Guanosine, 5'-Methyluridine.

  104. Nucleotide faq id: 752

    Nucleotides are structural components of our genetic code. Each nucleotide is composed of a nucleoside (Adenosine, Cytidine, Guanosine, or 5'-Methyluridine) and a phosphate bond. A nucleotide forms a single unit of our DNA.

  105. Nucleus faq id: 753

    The membrane-bound organelle containing the chromosomes.

  106. Null faq id: 754

    A NULL value is when there has been a mutation that prevents a reading for a  Y-chromosome DNA (Y-DNA) STR (Short Tandem Repeat) from being obtainable. It may be an actual deletion of the entire STR. It may also be caused by a change in DNA values such that the primer does not work.

  107. Organelle faq id: 755

    An organelle is a part of a cell that performs a specialized function. Examples are the nucleus and the mitochondrion.

  108. Outbreed faq id: 756

    Outbreed is when an individual's parents' common ancestry was more than ten generations in the past.

  109. P Arm faq id: 757

    The P Arm is the shorter of two sides to a chromosome.

  110. Palindrome faq id: 758

    A palindrome is something that reads the same way in either direction. In genetic genealogy, it is a sections of DNA that read the same way. It is most significant for Y-chromosome DNA because palindromes may be copied over each other.

  111. Parallel Mutation faq id: 759

    A parallel mutation is when the same genetic change happens in completely unrelated lineages.

  112. Pherogram faq id: 760

    For STRs, a plot which shows the length of a fragment of DNA. This allows its allele value to be measured.

  113. Phylogenetics faq id: 761

    Phylogenetics is the study of how genetics can be used to show how people are related.

  114. Phylogenetic tree faq id: 762

    A phylogenetic tree is the reconstruction through genetics of a lineage.

    See Also: Y-chromosome Consortium (YCC) Tree

  115. Polymerase faq id: 763

    The enzyme that starts the process of making nucleic acids or assembling RNA or DNA.

  116. Polymerase Chain Reaction (PCR) faq id: 764

    A technique allowing the production of multiple copies of extremely small amounts of DNA fragments using DNA polymerase and specific primers.

  117. Polymorphism faq id: 765

    In genetics, a polymorphism refers to there being more than one possible value at a locus, a specific location, in the genetic code of a population group.

  118. Population faq id: 766

    A population is a group of people who inhabit a geographic region or share a common origin.

  119. Population Bottleneck faq id: 767

    A population bottleneck is when a population is greatly reduced in size.

  120. Primer faq id: 768

    A short DNA sequence used in the polymerase chain reaction to initiate DNA synthesis at a particular location.

  121. Protein faq id: 769

    The main building block of our cells. Each one has a specific function.

  122. Principal Component Analysis (PCA) faq id: 770

    Principal component analysis is a mathematical method that attempts to separate an admixed dataset (here a genetic profile) into one or more contributing groups.

    Principal component analysis was invented by Karl Pearson in 1901 and is sometimes called the Karhunen-Loève transform or proper orthogonal decomposition

  123. Recombinational Loss of Heterozygosity (recLOH) faq id: 772

    Recombinational Loss of Heterozygosity (recLOH) is a process by which one copy of genetic code is copied over others. The result is identical values. In genetic genealogy, this is most significant for the Y-chromosome. Palindromic STR (short tandem repeat) markers may be copied over each other.

    For example, DYS385 may have a,b values of 12,19 for a father. His son may have values of 12,12. This is a single recLOH event.

  124. Recombination faq id: 773

    Recombination is the mixing of the DNA on each chromosome that you receive from your mother and father. Different chromosomes and different parts of each chromosome are more or less likely to recombine in a single generation.

  125. Replication faq id: 774
  126. Restriction Enzyme faq id: 775

    A protein that recognizes a certain sequence of DNA and cuts the DNA at that site.

  127. Restriction Fragment Length Polymorphism (RFLP) faq id: 776
  128. Sephardic faq id: 778

    Sephardic is the branch of the Jewish population that settled in Spain during the Jewish Diaspora.

  129. Sequencing faq id: 779
  130. Sex Chromosome faq id: 780

    The X- or Y-chromosome. Normally males have one X and one Y and females have two Xs.

  131. Short Tandem Repeat (STR) faq id: 781

    A short DNA motif (pattern) repeated in tandem. ATGC repeated eleven times would give the marker a value or allele of 11.

  132. Single Nucleotide Polymorphism (SNP) faq id: 782

    A SNP, Single Nucleotide Polymorphism, is a change in your DNA sequence at a locus, a specific location.

  133. Sister clade faq id: 783

    A sister clade is one of two haplogroup or subclade that are at the same level on a phylogenetic tree. For Y-chromosome research, this is sometimes a brother clade.

    For example, on the maternal tree, and H6a and H6b are sister clades. 

  134. Subclade faq id: 784

    A subclade is a minor branch of the human genetic trees. This may be either the Y-chromosome tree or the mitochondrial tree. Subclades are more specific to a location or population group than the major branches (haplogroups).

  135. Surname faq id: 785

    A last name or family name traditionally passed down from father to son.

  136. Telomere faq id: 786

    A telomere is the end of a DNA chromosome. Each of our autosomal and sex chromosomes has two telomeres.

  137. Thymine faq id: 787

    The "T" of the four bases that make up DNA. The other bases are adenine (A), cytosine (C), and guanine (G). Thymine always pairs with adenine.

  138. Time to the Most Recent Common Ancestor (TMRCA) faq id: 788

    The amount of time or number of generations since individuals have shared a common ancestor. Since mutations occur at random, the estimate of the TMRCA is not an exact number (i.e., 7 generations), but rather a probability distribution. As more information is compared, the TMRCA estimate becomes more refined.

  139. Transition faq id: 790

    A transition is a type of change in the genetic code (mutation). Examples are A <-> G and C <-> T.

  140. Transmission Event faq id: 791

    The passage of genetic material from one generation to the next.

  141. Transversion faq id: 792

    A transversion is a type of change in the genetic code (mutation). Examples are A <-> C and G <-> T.

  142. Unique Event Polymorphism (UEP) faq id: 793
  143. Western Atlantic Modal Haplotype (WAMH) faq id: 794

    The most common Y-DNA haplotypes found in Europe's most common Y-DNA haplogroup, R-M269.

  144. X-chromosome faq id: 795

    One of the two sex chromosomes, X and Y. X is the sex chromosome that is present in both sexes, singly in males and doubly in females.

  145. Y-chromosome faq id: 796

    One of the two sex chromosomes, X and Y. The Y-chromosome passes down from father to son. Females do not receive it. As the Y-chromosome is passed on through the paternal line, it is valuable for surname based genealogy studies.

  146. Y-chromosome Consortium (YCC) Tree faq id: 797

    A graphic representation of the Y-DNA haplogroups according to the Y-Chromosome Consortium (YCC) classification. Haplogroup names and major clades are labeled and mutation names are given along the branches of the trees.

    The current version of the tree is the YCC2010.

  147. Most Distant Known Ancestor (MDKA) faq id: 1677

    Your most distant known ancestor (MDKA) is the furthest person who you have documented on a specific genealogical line. In genetic genealogy, it usually refers to someone on a direct maternal line (the mother, her mother, her mother's mother, etc.) or to a direct paternal line (the father, his father, his father's father, etc.).

  148. Most Distant Known Origin (MDKO) faq id: 1678

    Your most distant known origin (MDKO) is the place of origin of the furthest person who you have documented on a specific genealogical line. In genetic genealogy, it usually refers to the birthplace of someone on a direct maternal line (the mother, her mother, her mother's mother, etc.) or to a direct paternal line (the father, his father, his father's father, etc.). However, where you know your ancestor was the descendant of immigrants but you only know the country of immigration, the MDKO is said to be unknown.

  149. RSRS (Reconstructed Sapiens Reference Sequence) faq id: 2089

    The Reconstructed Sapiens Reference Sequence (RSRS) is a mitochondrial DNA (mtDNA) reference sequence that uses both a global sampling of modern human samples and samples from ancient hominids. It was introduced in early 2012 as a replacement for the rCRS (revised Cambridge Reference Sequence). Because it is based on the likely modal haplotype of the common ancestor to both modern humans and such ancient groups as the Neanderthals, it shows an unbiased path back from any one modern mtDNA sequence to our distant common maternal ancestor.