Genetics Part III

The instructions that make an individual grow, develop and acquire specific characteristics and make it a unique individual reside in the chromosomes found in the nucleus of the cell, each chromosome is built up of curled double filaments made of DNA and proteins, these double helixes are divided into segments called genes. Each gene carries information that will allow it to produce a specific protein which will dictate to the cells what function they will perform whether it is the production of pigments, keratin, tissues and all other hereditable characteristics.

HISTONES

DNA & PROTEINS

CENTROMERE

TELOMERE

A GENE

DOUBLE HELIX OF DNA

BASE

LOCUS

GENE

HOMOLOGOUS CHROMOSOMES

Alleles are alternate forms of a gene which are inherited independently from each parent, these alleles may be alike or similar in which case the subject is said to be a homozygous, or they may be different, in which case the subject is heterozygous for a given character. The locus is the specific place where the gene can be located.

PATERNAL

MATERNAL

DIFFERENT ALLELES

SIMILAR ALLELES

NUCLEUS

Fertilization is the process by which genetic material from both parents comes together in a zygote, each sexual cell contains 20 pairs of chromosomes which represents half (n) of the amount assigned to the species, in this case canaries, after this union they become 40 pairs (2n) of chromosomes. Meiosis is a two stage multiphase process that reduces the chromosomal content when producing the germinal cells to its haploid content (n) once again to complete the sexual reproduction life cycle.

The significane of these processes for CANARICULTURE is that:

· Two chromosome variants come together, each parent offers half of their chromosomes.

· Chomosomes replicate and reorganize randomly to form new combinations.

· Crossover of genetic material occurs.

· Provides opportunity for the appearance of new genetic variations.

ALLELE