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Crossbreeding
terminology
Allele One of two or more forms of a
gene at a particular location on a
chromosome. For example, blue and
brown eyes are determined by different
alleles of the gene for eye colour.
Chromosomes rod-like structures that
are found in the nucleus of all cells. These
structures contain genetic information and
occur in pairs.
Co-dominant two alleles that contribute
to a trait.
Complementarity
Combining two
breeds to overcome defects in one or both
breeds.
Crossbreeding
Combining existing
breeds to produce a hybrid which has a
combination
of
the
inheritable
characteristics of the parent breeds.
Dominant
an allele that masks the
expression of another.
F1
First generation following the
crossing of two breeds, and refers to Filial
1 . For example, the progeny of a cross
between a Limousin and an Angus would
be referred to as the F1.
Gene a portion of the chromosome that
makes up the complex coding system that
directs enzyme and protein production.
Genes code for specific traits and govern
how these traits will develop and be
expressed.
Genotype The particular set of genes of
an animal for a characteristic.
Heterozygous Two different alleles of a
particular gene.
Homozygous
Two identical alleles of a
particular gene.
Hybrid
T h e o ffspring from a cross
between individuals of two different
species.
Inbreeding Mating of closely related
parents, for instance, brother to sister,
mother to son.
Line-breeding Mating of relatively close
parents, for instance, brother to
grandmother, daughter to grandfather,
mother to cousin.
Mutation An inheritable alteration of
the genes or chromosomes
Outcrossing Mating of parents that are
several generations apart.
Phenotype
The genetically and
environmentally determined physical
appearance of an animal.
Recessive
the allele that would be
masked by the dominant allele.
Sex chromosomes
the X and Y
chromosomes that determine gender.
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FARMING AHEAD No. 77 - May 1998