Body cells having the diploid number of chromosomes; all cells of the body other than gametes.
Reporductive cells (eggs and sperm) which have a haploid or single set of chromosomes.
Organ in which gametes are formed (ovary and testis in animals; gametophytic organs in plants)
Regular cell division in which there is an exact quantitative and qualitative replication of each chromosome, one going to each of two daughter cells.
The type of cell division which occurs during the formation of gametes in which the diploid number of chromosomes found in body cells is reduced to the haploid number (2n to n). In this process each gamete receives one, and only one, member of each homologous pair of chromosomes.
Referring to cells with the double or 2n number of chromosome characteristics of all body or somatic cells except mature gametes.
Referring to cells with a single set, or n number of chromosomes, characteristic of mature gametes.
A chromatin body found in the nucleus of cells which bears genes arranged in a definite order along its length, and which acts as a unit during mitosis and meiosis.
A particular chromosome which determines or influences the sex of an individual (in many animals including man: XX=female, XY=male) and bears the sex-linked genes.
Any and all chromosome except the sex chromosome.
Any pair of chromosomes which have the same linear arrangements being derived at fertilization from the egg (maternal chromosomes) and the other from the sperm (paternal chromosome)
Defined classically as a hereditary unit, located at a particular position on a particular chromosome.
Two genes with the same or differing genetic effects occupying corresponding locations on the two members of a homologous chromosome pair.
Referring to both alleles are the same for a trait - homozygous dominant = AA (pure breeding) - homozygous recessive = aa (pure breeding)
Referring to one of each allele is present: Aa (Not necessary to say heterozygous "dominant" since in the heterozygous condition the dominant allele will always be expressed.
Referring to only one allele present , as in sex-linked inheritance (X - expressed allele, Y - basically only "maleness")
The genetic constitution of an individual (e.g., BB, Bb, or bb)
The appearance of the individual, irrespective of the actual genetic constitution (e.g., in the case of dominance, BB and Bb would have the same appearance)
A gene which when present is able to suppress the phenotypic expression of its unlike allele (e.g., gen A, B, or, C)
A gene which is unable to express its phenotypic effect in the presence of its dominant allele.
Partial or incomplete dominance
The absence of dominance; both members of an unlike pair of allelic genes are able to partially express their phenotypic effect in the presence of the other allele.
The expression of a gene which causes death when homozygous.
Test Cross or Back Cross
The crossing of a phenotypically dominant individual of unknown genotype (Ex. A_B_) to a homozygous recessive individual to determine the genotype of the test animal.
A spontaneous chemical change within a gene that changes the phenotypic effect of the gene in successive generations.
The separation of the members of homologous pairs of chromosomes during meiosis, with the result that each gamete receives one member of each pair of chromosomes.