Genetics Flashcards
Phenotype
The observable characteristics of an individual, usually resulting from the interaction between the organisms genotype and the environment in which it develops
Monogenic
Phenotype controlled by 1 gene
Polygenic
Phenotype controlled by many genes
Gene
A triplet sequence of nucleotide bases, found on the DNA strand, that codes for the production of a polypeptide.
Allele
One of a number of alternating forms of the same gene, responsible for determining varying characteristics. The nucleotide sequence of the gene varies to give different alleles.
Locus
Position of an allele on the DNA molecule aka the chromosome
Homozygous
The diploid condition in which the alleles at a given locus are identical
Heterozygous
The diploid condition in which the alleles at a given locus are different
Dominant
The allele which influences the appearance of the phenotype even in the presence of an alternative allele
Recessive
The allele which influences the appearance of the phenotype only in the presence of another recessive allele
F1 generation
The generation produced by crossing HOMOZYGOUS parental stocks (for e.g WW x ww)
F2 generation
The generation produced by crossing two F1 organisms ( Ww x Ww)
Genotype
The genetic constitution of an organism with respect to the alleles under consideration
Law of Segregation
A pair of alleles separates during gamete formation, as only one allele can be carried by each gamete. So, the members of an allele pair are found in two different gametes - one in the maternal and the other in the paternal. This segregation of alleles occurs during anaphase 1 of meiosis, when the bivalents separate
Law of independent assortment
Based upon evidence from the dihybrid cross, Mendel concluded that the presence of one type of allele (allele A/a)in a gamete does not affect which type of allele will be present for another trait (Allele B/b). The two genes segregate independently of each other during meiosis.
