HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lush, J. L. Search for Related Content PubMed PubMed Citation Articles by Lush, J. L.

Dairy Cattle Breeding

Importance of Family Structure in the Dairy Cattle Population¹

Department of Animal and Dairy Science, Iowa State University, Ames

ABSTRACT

Biological populations always have some kind of family structure. In this they differ from populations of inanimate objects, such as numbered balls or tickets in an urn, where every individual is independent of all the others.

Family structure refers to relationship by descent. When individuals are grouped according to their own phenotypes, the resulting groups are called grades, types, or classes. They are not called families. The difference between the two kinds of groupings is profound. It is like interchanging the dependent and the independent variables in a regression.

Relationship is the probable likeness (expressed as a correlation) between a pair of genes in one individual and the allelic pair in another individual, merely because they are related by descent. It is also the probable likeness of their whole genotypes if nonallelic genes are combined at random, i.e., if the mating system was based purely on consanguinity, with no attention at all to phenotypic likeness or unlikeness of mates.

¹ Presented at the Sixty-second Annual Meeting of the American Dairy Science Association, Cornell University, Ithaca, New York, June 1967.