By Doug Oettinger
Understanding basic breeding and genetic terms is not very difficult. However, if it’s not something you use on a daily basis, hearing or reading a word or phrase may leave a person scratching their head and saying, “Huh?” In the world of poultry farming, there are some basic genetic and breeding terms you may hear. While it does not include everything
By any means, here are some key terms you may come across and their definitions.
Reproduction and mating:
swarm of luck. In the poultry world, flock mating simply allows a flock of chickens and roosters to reproduce freely. Flock eggs are incubated, either naturally or in an incubator, as a way to generate new offspring. This is the method used to generate larger quantities of new offspring. In flock mating, birds that do not meet ideal standards are often removed or excluded from the flock, in order to maintain high quality and set standards within the flock.
line breeding. Breeding is a controlled process of breeding closely related animals – within a family or breed to the desired concentration
traits within the group. It may mean that the females are reborn
Father or grandfather, or half-siblings intermarry. because of
Inbreeding included, there is also the possibility of taking out unwanted items
Features. Breeding breeds requires a willingness and ability to exclude and remove from the breeding program any birds that do not meet standards or have less than desirable traits. In line breeding programmes, a detailed history is kept, showing which birds or animals were mated together and details of the lineage of the flock. Breeding is common in cattle, sheep and poultry improvement schemes.
genetics terms:
allies. Allele technically refers to a gene that is part of a pair of genes, at the same locus on a pair of chromosomes. Sometimes you may see the word allele in place of the word gene.
automatic. Any chromosome other than the sex chromosome.
chromosomes. These are segments of DNA (short for deoxyribonucleic acid). These are found within the nucleus or center of the cell. These “genes” are linked. Chromosomes are found in pairs in all cells, except for sex cells (egg and sperm cells). Sex cells contain only half of each group, or
Husband. Thus, when the egg and sperm meet together, the new one grows
An organism will receive half of its chromosomes from the mother,
Half of her chromosomes are from the father. The term chromosome
literally means “colored body”, since these are seen under a microscope,
After preparatory staining or coloring.
Each type of animal or plant has its own number of chromosomes in the cell nucleus. Chickens contain 39 pairs or 78 individual chromosomes in each
cell.
mitigation / mitigation. In the world of genetics, there are colors and patterns that may change or be less pronounced due to one or more genes within the genome. These are often known as ‘dilution genes’. One such example is the lavender or “self blue” plumage in chickens. There are two recessive genes in the genetic makeup of birds, which dilute or alter both the black and brown or red tints in the plumage, causing them to have a lavender or “blue” color (in fact it is a shade of light gray). When two blue birds are self-bred, each will produce a blue offspring. In fact, there are at least two other known groups of
Modifying or assisting genes that work in conjunction with autologous blue
genes to make it happen.
You may sometimes hear the term “soft ban”. In this case, it means that there is only one sex-linked prohibition gene. The blocked pattern will still be there, but it may be less clear and obvious. Hence, the term “dilute”.
dominant gene. A gene that, by itself, will cause an organism to exist
specific adjective. In naming or writing about genetics, they are always
with a capital letter.
Game. reproductive cell. It can be either an egg or a sperm.
genes. These are actually just shorter pieces of DNA attached and lined up along the edges of the chromosomes. Genes possess the blueprint or “code” that determines what an animal or plant will look like and what traits it will have.
genome. The complete picture of all genes and chromosomes combined, in an animal or plant.
Genomics. The study of genetics at the cellular and molecular level.
Genotype. This refers to the actual genetic makeup in the cells of the organism. To date, more than 23,000 genes have been identified in the humble little chicken.
germ cell. The same gamete.
Heterogeneous. This refers to the difference in the sex chromosomes that the organism carries. For example, in chickens, the female is heterogametic. she has
Both AZ (“male” sex chromosome) and W (“female” sex chromosome) are in their genome, or genetic makeup.
heterozygos. This means that only one of the genes for a particular trait is carried by the animal or plant.
monolithic. This means that an organism carries two of the same
sex chromosomes. In chickens, males are homozygous, carrying two Z chromosomes in their genome.
homozygos. Two genes for the same trait carried by an animal or plant.
Jane the Killer. These are the genes that when two genes (in A
homozygous state), usually causes the organism to die during development,
or shortly after hatching or birth. These genes are usually recessive.
LOCUS (plural: LOCI). This is simply the “location” of where the gene is located on the chromosome.
Modifying or “helper” genes. These are genes that, in some way, modify or alter the effects of other genes. Indeed, many genes act on each other, to some extent, as modifiers.
leap. A change in the actual molecular structure of the gene. these
Changes can be good or bad. Such a mutation may then bring about a physical change in the actual structure of the new organism.
Phenotype. This refers to what an animal or plant looks like.
recessive genes. These genes are always identified by lowercase letters in the nomenclature, and require two of them, working together, to give the organism a particular trait.
sex chromosomes. Chromosomes that determine the sex of an organism. In birds, these are called Z and W chromosomes. Males have two Z chromosomes; Females have one Z and one W chromosome.
sex-linked genes. A gene linked to the Z or W sex chromosome. In birds, most sex-linked traits are due to a gene located in the male, or Z chromosome. One example is the dominant gene for black and white
Feathers bearing a Z are prohibited in birds. Breeding and genetics are fascinating because of the endless variations that often appear in any breeding project. The sky is the limit, the possibilities are endless. What hidden genetic secrets can you discover about your birds?
Doug Oettinger He lives, works, and writes from his small hobby farm in northwest Minnesota. Doug’s educational background is in agriculture
with an emphasis in poultry and bird science.