lecture27 - Lecture 27 Effects of Inbreeding Today we will...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 27 Effects of Inbreeding: Today we will examine how inbreeding between close relatives (also known as consanguineous matings) influences the appearance of autosomal recessive traits. Note that inbreeding will not make a difference for dominant traits because they need only be inherited from one parent or for X-linked traits since they are inherited from the mother. Consider an extreme case of inbreeding namely a brother-sister mating. ? A useful concept is the Inbreeding Coefficient = F which is defined as the likelihood of homozygosity by descent at a given locus. If we consider a locus with different alleles in each grandparent: A1 , A2 , A3 , A4 , F is the probability that the grandchild will be either A1 / A1 , A2 / A2 , A3 / A3 , A4 / A4 p( A1 / A1 ) = 1 / 2 . 1 / 2 . 1 / 4 = 1 / 16 " p( A2 / A2 ) = = 1 / 16 " p( A3 / A3 ) = = 1 / 16 " p( A4 / A4 ) = = 1 / 16 p(homozygous by descent) = 4 . 1 / 16 F = 1 / 4 A bother-sister mating is the simplest case but is of little practical consequence in human population genetics since all cultures have strong taboos against this type of consanguineous mating and the frequency is extremely low.
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern