becker.chicken {agridat} | R Documentation |
Mating crosses of chickens
data("becker.chicken")
A data frame with 45 observations on the following 3 variables.
male
male parent
female
female parent
weight
weight (g) at 8 weeks
From a large flock White Rock chickens, five male sires were chosen and mated to each of three female dams, producing 3 female progeny. The data are body weights at eight weeks of age.
Becker (1984) used these data to demonstrate the calculation of heritability.
Walter A. Becker (1984). Manual of Quantitative Genetics, 4th ed. Page 83.
None
data(becker.chicken) dat <- becker.chicken if(require(lattice)){ dotplot(weight ~ female, data=dat, group=male, main="becker.chicken - progeny weight by M*F", xlab="female parent",ylab="progeny weight", auto.key=list(columns=5)) } ## Not run: # Sums match Becker sum(dat$weight) aggregate(weight ~ male + female, dat, FUN=sum) # Variance components require(lme4) require(lucid) m1 <- lmer(weight ~ (1|male) + (1|female), data=dat) as.data.frame(lme4::VarCorr(m1)) ## grp var1 var2 vcov sdcor ## 1 female (Intercept) <NA> 1095.6296 33.10030 ## 2 male (Intercept) <NA> 776.7543 27.87031 ## 3 Residual <NA> <NA> 5524.4000 74.32631 # Calculate heritabilities s2m <- 776 # variability for males s2f <- 1095 # variability for females s2w <- 5524 # variability within crosses vp <- s2m + s2f + s2w # 7395 4*s2m/vp # .42 male heritability 4*s2f/vp # .59 female heritability ## End(Not run)