Got a YouTube account?

New: enable viewer-created translations and captions on your YouTube channel!

English subtitles

← Inbreeding

Get Embed Code
1 Language

Showing Revision 2 created 10/02/2013 by Cogi-Admin.

  1. Inbreeding, which is just sexual relations between close
  2. family members or close relatives, blocks a certain
  3. amount of genetic shuffling and maximizes the chances
  4. that recessive traits will be uncovered in offspring. Now
  5. this happens often times because family members share
  6. common ancestors. And if you have an affected
  7. relative at some point in the family tree.
  8. Let's say this is a recessive trait. That means
  9. that he, he's homozygous recessive for this. He has
  10. to pass at least one allele on to the
  11. offspring. We're going to assume they're heterozygous here even though
  12. we don't know that, but they have at least
  13. one recessive allele. And then if they pass that
  14. down to their offspring, here we have first cousins.
  15. If they were to produce a child at this
  16. point, there's a significant chance that that child could
  17. inherit both recessive alleles. One from each parent.
  18. So what this means, is that when you are
  19. a carrier of a particular allele that's hidden
  20. because the trait is recessive, if you go out
  21. in the general population, almost no one's going
  22. to be affected by this. Because in general, disease
  23. traits like this are rare one in 20,000,
  24. one in 50,000. So going outside of your gene
  25. pool, will reduce the probability you're going to find anyone
  26. else with the same variant or allele. But when you
  27. stay within your own gene pool, there other individuals
  28. with the same alleles that you have. And if some
  29. of those alleles are deleterious or detrimental or alleles
  30. that you would rather not showing up in your offspring,
  31. you should avoid inbreeding. Because there is a much
  32. higher chance that those alleles are going to show up in
  33. homozygous condition and affect your offspring
  34. or your children. Ultimately, inbreeding defeats
  35. the success of meiosis, specifically the
  36. recombination in independent assortment parts. Evolution
  37. has gone to great lengths to ensure that the meiotic processes of
  38. sexual reproduction are ingrained in every
  39. living thing. Because mixing and matching alleles
  40. is a really important part to a population
  41. and a species survival. So when individuals mate within
  42. their gene pool, all of the effort that
  43. meiosis goes to, to make sure there are lots
  44. of different alleles to choose from and, and,
  45. and recombine with, it's kind of defeated. Because you're
  46. staying in a gene pool that has the same
  47. alleles available. So there's a much higher probability that
  48. any bad alleles are going to show up in homozygous condition in the offspring.