NextGen Genealogy: The DNA Connection by David R. Dowell

by DerdriuMarriner

NextGen Genealogy: The DNA Connection by David R. Dowell links atDNA, mtDNA, xDNA, and yDNA genetic testing to family history and health history research.

DNA assists family history and health history problem-solving

NextGen Genealogy: The DNA Connection addresses the ways that genetic testing confirms or contradicts family histories, genealogical research, and pedigree charts. David R. Dowell brings to genetic genealogy his expertise as a history and library science multiple degree-holder. Dr. Dowell calls upon experiences as:
• Air Force special investigative officer;
• American Library Association genealogy committee chair;
• Crash Course in Genealogy author;
• Cuesta College, Duke University, Illinois Institute of Technology, Iowa State University, and Pasadena City College academic librarian;
• Dr D Digs up Ancestors blogger;
• family genealogist and historian since the 1960s;
• haplogroup and surname database manager;
• International Society of Genetic Genealogists member;
• Middle Tennessee Genealogical, National Genealogical, New England Historic Genealogical, and Southern California Genealogical Societies member.




Although commonly depicted as an "orange sausage with a blob inside of it" (as shown here), mitochondria may take many shapes.

diagram of mitochondrion
diagram of mitochondrion

DNA exists in every cell's mitochondria and nucleus


The info-book divides into eight chapters preceded by a four-page preface with acknowledgments and notes and succeeded by 14 pages of bibliography, glossary, and index.

The 16-page first chapter explains deoxyribonucleic acid as:

  • mitochondrial DNA (mtDNA) in the food-energizing mitochondria surrounded by the cytoplasm between the cell membrane and the cell nucleus;
  • nuclear DNA in 22 pairs of autosomes and one pair of gender-differentiating sex chromosomes in the cell nucleus.

It furnishes questions to answer regarding genealogical research untangling adoption, brick-wall roadblocks, ethnicity or surname origins in order to match genetic test type with genetic testing motivations of:

  • curiosity;
  • data preservation in more durable forms than human memory;
  • family history research;
  • health history and personalized genome medicine. 


typical mitochondrial network (green) in two human cells (HeLa cells)

fluorescent microscopy
fluorescent microscopy

DNA identifies ancestors, ethnicity, relatives through four tests


The 26-page second chapter goes over Y-chromosome testing of male DNA (yDNA) which disproves relationships more conclusively than it establishes definitive lines of descent and which fathers transmit only to sons.

The 15-page third chapter handles mitochondrial DNA which daughters and sons inherit from mothers, survives after all other DNA expires, and traces female lines back into the deep past.

The 33-page fourth chapter identifies autosomal DNA (atDNA) which daughters and sons inherit at the rate of one each from both parents regarding 22 pairs of autosomal chromosomes and which may detect third, fourth, and fifth cousins.

The 11-page fifth chapter juggles X-chromosomes (xDNA) which daughters inherit from both parents and sons from mothers regarding female lines. 


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DNA merges eight-generation pedigree charts, extreme haplogroup genealogy


The 22-page sixth chapter knits male and mitochondrial DNA into the extreme genealogies of haplogroups (most ancient common ancestors) known as:

  • Y-chromosome Adam 338,000 years ago;
  • Mitochondrial Eve 140,000 years ago.

Extreme genealogy leads descendants from eight-generation pedigree chart ideals to expansions from Africa 120,000 to 150,000 and 55,000 to 75,000 years ago to:

  • Asia 40,000 to 70,000 years ago;
  • Australia 40,000 to 60,000 years ago;
  • Europe 35,000 to 50,000 years ago;
  • Americas 15,000 to 35,000 and 8,000 to 10,000 years ago.

The 25-page seventh chapter mentions genetic testing as ethnically balancing or imbalancing technology and values.

The five-page eighth chapter notes in conclusion optimal results from testing three-plus generations of as many close relatives as possible. 


NextGen Genealogy: The DNA Connection by David R. Dowell ~ Available now via Amazon

Describes 3 major categories of DNA testing for family history research: Y-chromosome tests for investigating paternal (surname) lines, mitochondrial tests for investigating maternal (umbilical) lines, and autosomal tests for exploring close relationships
genealogy resources



My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.


Sources Consulted


Dowell, David R. 2014. NextGen Genealogy: The DNA Connection. Santa Barbara, CA, USA; Denver, CO, USA; Oxford, England, UK: Libraries Unlimited. 


Nuclear versus mitochondrial DNA:

Unlike nuclear DNA (left), mitochondrial DNA is only inherited from the maternal lineage (right).
University of California Museum of Paleontology (UCMP) and the National Center for Science Education
University of California Museum of Paleontology (UCMP) and the National Center for Science Education
the end which is also the beginning
the end which is also the beginning

Mitochondrial Eve By: PASIEKA ~ Available as Photographic print and as Premium photographic print ~ Available now via

Scientific illustrator/photographer Alfred Pasieka's concept of circular molecule of mitochondrial deoxyribonucleic acid, only inherited maternally; Mitochondrial Eve lived about 200,000 years ago in Africa, left unbroken line of daughters to present day.
Mitochondrial Eve

Me and my purrfectly purrfect Maine coon kittycat, Augusta "Gusty" Sunshine

Gusty and I thank you for reading this article and hope that our product selection interests you; Gusty Gus receives favorite treats from my commissions.
DerdriuMarriner, All Rights Reserved
DerdriuMarriner, All Rights Reserved
Updated: 11/13/2021, DerdriuMarriner
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DerdriuMarriner on 03/23/2017

katiem2, It also shows up in medical genealogy which is like traditional ancestor-hunting but the charts map health problems, such as a tendency toward tuberculosis, from generation to generation.

katiem2 on 03/19/2017

True, so true and imagine how it helps us to maintain good health and avoid issues that could threaten it if gone unchecked. I suppose that is a whole other topic in itself.

DerdriuMarriner on 03/18/2017

katiem2, The DNA connection is so interesting in how it helps with the ancestors that we can put names on and with those that we just can put into groups, like Denisovan descendants in the Old Southwest.

katiem2 on 03/18/2017

After reading this I dug up my old family tree dna, fascinating...

DerdriuMarriner on 03/15/2017

iggy, Thank you! It's fascinating to me how DNA can call up -- from way, way back -- ancient, anonymous ancestral and ethnic groups in addition to helping with the more recent ancestors that we know.

iggy on 03/11/2017

I love that dna can tell you where you are from and if you participated in a crime. Your article gave me more insight into what dna can do.

DerdriuMarriner on 03/10/2017

katiem2, It's so fascinating to see how far back one can go in DNA and traditional genealogies that respectively reveal ancestors by names and in DNA genealogy that reveals ancestral groups, such as Denisovan or Neanderthal.

katiem2 on 03/09/2017

DNA is a powerful answer to so many questions

DerdriuMarriner on 04/28/2016

blackspanielgallery, It's so fascinating how far back genetic testing takes one, from the domain of names into the nameless realms of Denisovans and Neanderthals! I hope the surprises all were pleasant for you and your wife.

blackspanielgallery on 04/16/2016

My wife had a DNA test with surprises. My heritage is so varied I cannot imagine anything else would show up, but I may try it one day soon.

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