Crossmatings were accomplished among three semi-closed lines within a population of pigs, for the purpose of investigating effects of crossbreeding on reproductive traits. Two of the lines were purebred (Berkshire and Yorkshire); the third line ("Composite") consisted of descendants from inter se matings among offspring of crosses of the Berkshire...
The relationships of serum T₄
(thyroxine) levels and liver
nicotinamide nucleotide coenzyme (NAD and NADP) levels with production
of traits of beef cattle were investigated at both weaning (182
kg) and following performance testing (363 kg). In addition, the value
of these parameters as selection criteria for improved performance
was...
An experiment was conducted to examine the responses to
selection for high and low rate of gain in the mouse under a system
whereby inbreeding was maximized. Rate of gain was measured by an
index designed to include gains in both the pre- and postweaning
periods with the gains in...
An F₁ population resulting from mating pygmy and normal goats (local commercial breeds) was crossed to give an F₂ population. Analysis of wither height and body weight indicated that the F₂ population was intermediate between the parental types (pygmy and normal) with little overlap of phenotypic values for body size...
An experiment was conducted to determine if selection from
standardized litters would be effective in separating lines of mice
selected for increased and decreased litter weight at 14 days of age,
and if response to selection on this maternally influenced trait could
be accurately predicted.
Data were collected on litter...
Tuberous sclerosis is a serious heritable human disorder
that involves many organ systems. It was first recognized as a
disease entity over a century ago. Its mode of transmission in
familial cases has been fairly well established to be that of a single
gene locus autosomal dominant trait. However, the...
An investigation of the effects of exogenous gonadotropic
treatments on fertility of various genetic groups of ewe lambs were
run over a six-year period. Since hormonal treatments varied and
the experimental animals were different from one breeding season to
the next, each year comprised a separate study. Hormone treatment
included...
The present investigation with the chromosomes of Zea mays
was conducted to determine: (1) the effects of chelating agents on the
process of cytological exchange, and (2) the effects of chelating agents
on genetic recombination.
To ascertain the influence of chelating agents on cytological
exchange, four known heterozygolis paracentric inversion...
The relationship between x-ray induced chromosome aberrations
and x-ray induced embryonic abnormalities was studied. Golden
hamsters were irradiated during four stages of gestation: the blastocyst
stage, 4.5 days post-copulation; the primitive streak stage, 6.5
days post-copulation; the organogenesis stage, 9.5 days post-copulation;
and the period of fetal growth, 11.5 days...