Anthro Lecture 2-28 - Anthro Lecture 2-28 I Heritability(h2...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Anthro Lecture 2-28 I. Heritability (h 2 ) a. Basic Explanation i. Heritability of a trait – The proportion of phenotypic variation that is attributable to genetic variation ii. Varies from 0.00 to 1.00 iii. Vt = total phenotypic variation in a trait iv. Vg = amount of phenotypic variation due to genetic variation v. Ve = amount of phenotypic variation due to environmental variation vi. Vt = Vg + Ve vii.h 2 = Vg/Vt viii. If h 2 = 0, none of the phenotypic variation is due to genetic variation ix. If h 2 = 1, all of the phenotypic variation is due to genetic variation b. Estimating h 2 i. Comparisons between monozygotic (MZ) and dizygotic (DZ) twin pairs 1. To the extent that MZ twins are more similar, heritability is higher ii. Correlations between identical twins reared apart 1. Any similarity above chance levels implicates genetic contribution to variation iii. Comparisons between adoptive and genetic co-reared siblings 1. To the extent that genetic sibs are more similar, heritability is higher c. Use i. Developed originally to use in agriculture (breeding animals and plants) ii. Also useful for assessing the potential for natural selection to operate on a trait (remember that Darwin’s postulates include heritability)
Image of page 1

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

View Full Document Right Arrow Icon
iii. But it is not the same as “the proportion of the trait that’s attributable to genes” which is immeasurable and meaningless iv. …specifically 1. h 2 tells you about the sources of variation among individuals, not the relative roles of genes and environment in individual development (recipe analogy) 2. h 2 is specific to a particular population at a particular point in time, because changes in either the population’s genetic make-up or its environment will change the value of h 2 . Two genetically identical populations could have different values of h 2 for the same trait v. Take-home message 1. It’s meaningless to speak of THE heritability of trait x, because h2 can
Image of page 2
Image of page 3
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