Genetics Flashcards
(18 cards)
Gene
A small portion of DNA coding for a particular characteristics.
Alleles
Different forms of a gene which occur at the same locus (position) on homologous chromosomes.
Genotype
Genetic composition (make - up) of an organism.
Phenotype
The physical appearance of an organism determined by the genotype, eg. Talk, short.
Dominant allele
An allele that is expressed (shown) in the phenotype when found in the hetero zygote (Tt) and homozygote (TT) condition.
Recessive allele
An allele that is masked (not shown) in the phenotype when found in the heterozygote (Tt) condition. It is only expressed in the homozygote (tt) condition.
Heterozygote
Two different alleles for a particular characteristics eg. Tt.
Homozygous
Two identical alleles for a particular characteristics eg. TT or tt
Monohybid cross
Only one characteristic or trait is being shown in the genetic cross.
Complete dominance
A genetic cross where the dominant allele masks (blocks) the expression of a recessive allele in the heterozygous condition.
Incomplete dominance
A genetic cross between two phenotypically different parents produces offspring different from both parents but with an intermediate phenotype.
Co-dominance
A genetic cross in which alleles are expressed equally in the phenotype.
Multiple alleles
More than two alternative forms of a gene at the same locus.
Sex-linked characteristics
Characteristics and traits that are carried on the sex chromosomes.
Karyotype
The number, shape and arrangement of all the chromosomes in the nucleus of a somatic cell.
Cloning
Process by which genetically identical organisms are formed using biotechnology.
Genetic modification
The manipulation of the genetic material of an organism to get desired changes.
Human gemone
The mapping of the exact position of all the genes in all the chromosomes of a human.
