Accumulating DNA mutations through time, Mark Stoneking

Interviewee: Mark Stoneking. Geneticist Mark Stoneking talks about the difficulties of measuring time by mutations. (DNAi Location: Applications > Human origins > Gene genealogy > A molecular clock? > Counting DNA mutations)

And so if you have a particular nucleotide at one position, say an A, and when it mutates it will change to a G, a C, or a T, just something else. And now, if you look over a long enough evolutionary period of time, that particular point in the DNA segment has a probability of mutating again. And so, and because there's only three choices that it can mutate to, and be seen as a difference, there's a high chance that it will mutate right back to what it was before. So you could have an A mutate to a G, then the G mutates back to an A. And so you've had two mutations and yet, if you only compare, if all you see is an A in one species, and an A in the other, you will say there've been no mutations. So what we actually observe, the number of differences that we count is an underestimate, of the number of mutations that have actually occurred.

dna mutations,dna nucleotide,dna segment,mark stoneking,molecular clock,human origins,location applications,measuring time,time mark,interviewee,geneticist,probability,period of time,choices

Related Content

15178. Mitochondrial DNA and the molecular clock, Douglas Wallace

Geneticist Douglas Wallace explains a method of mapping a population's history using the mutations accumulated by its members.

  • ID: 15178
  • Source: DNAi

15166. Constructing our family tree, Mark Stoneking

Geneticist Mark Stoneking speaks about the findings of early mitochondrial DNA studies.

  • ID: 15166
  • Source: DNAi

15164. Fossils and human origins, Mark Stoneking

Geneticist Mark Stoneking, co-author of an early mitochondrial DNA paper, talks about the competing theories of human origins.

  • ID: 15164
  • Source: DNAi

15165. Mitochondrial Eve, Mark Stoneking

Geneticist Mark Stoneking, one of the authors of a controversial 1987 paper on mtDNA, talks about our common female ancestor.

  • ID: 15165
  • Source: DNAi

15529. Radiation can cause DNA mutations, 3D animation with narration

Mutations and the molecular clock.

  • ID: 15529
  • Source: DNAi

15091. Measuring age by mutation, Michael Hammer

Evolutionary geneticist Michael Hammer speaks about methods of measuring a population's age by the mutations in its individuals.

  • ID: 15091
  • Source: DNAi

15092. Studying the Y chromosome to understand population origins and migration, Michael Hammer

Evolutionary geneticist Michael Hammer speaks about the markers used to analyze DNA variation in the Y chromosome.

  • ID: 15092
  • Source: DNAi

15152. Isolating ancient DNA, Svante Paabo

Evolutionary geneticist Svante Paabo speaks about the limitations of working with DNA from fossils.

  • ID: 15152
  • Source: DNAi

15119. Shared genetic material between humans and chimps, Mary-Claire King

Geneticist Mary-Claire King talks about her discovery that chimps and humans are extremely similar at a molecular level.

  • ID: 15119
  • Source: DNAi

15980. Accumulating mutations

Mutations are the grist of evolution, and have accumulated in our DNA over time. When populations separate, each group accumulates their own unique set of DNA mutations.

  • ID: 15980
  • Source: DNAi