Types of Dominance

Vocabulary flashcards defining the three types of dominance discussed in the lecture transcript.

Complete dominance

A type of dominance where one allele is dominant and the other is recessive, such that the effect of the recessive allele is masked by the dominant allele in the heterozygous condition.

Incomplete dominance

A type of dominance where none of the two alleles of a gene is dominant over the other, resulting in an intermediate phenotype in the heterozygous condition.

Co-dominance

A type of dominance where both alleles of a gene are equally dominant whereby both alleles express themselves in the phenotype in the heterozygous condition.

Chromatid

Each of the two threads of a replicated chromosome

Gene

A segment of DNA in a chromosome that contains the code for a particular characteristic

Alleles

Different forms of a gene which occur at the same locus(position) on homologous chromosomes

Dominant allele

An allele that is expressed(shown) in the phenotype when found in homozygous and heterozygous condition

Recessive allele

An allele that is masked (not shown) in the phenotype when found in heterozygous condition. It is only one expressed in the homozygous condition

Phenotype

The physical appearance of an organism determined by the genotype eg tall or short

Genotype

Genetic composition (makeup) of an organism

Homozygous

Two identical alleles for a particular characteristic eg TT or tt

Heterozygous

Two different alleles for a particular characteristic eg Tt

Monohybrid cross

Only one characteristic shown in a genetic cross

Dihybrid cross

Two different characteristics shown in a genetic cross

Sex-linked

The allele causing the disorder is found on the X-chromosome