B17 - Inherited change Flashcards
What is a genotype?
Genetic constitution of an organism. It describes what alleles an organism has. The genotype determines the limits within which a characteristic of an individual can vary. This can be affected by other factors, such as diet
What is a phenotype?
Observable or biochemical characteristics. This is a result of an interaction between the expression of genotype and the environment
What is a gene?
It is a length of DNA or sequence of bases that code for a particular polypeptide
What is the position of a gene on a particular DNA molecule called?
A loci
What is an allele?
Alleles are alternative form of a gene. Some genes only have 2 forms, others can have more
What determines a phenotype?
A combination of alleles
How many alleles can be found on one chromosome?
1
Do diploid organisms have homologous pairs of chromosomes?
Yes
What is it called if the alleles are the same on the homologous pair?
Homozygous
What is it called if the alleles are different on the homologous pair?
Heterozygous
What is it called when both alleles contribute to the phenotype?
Codominant
What is pure breeding?
Pure-breeding is repeated breeding of organisms for a particular characteristic. The organism will be homozygous for this gene
What is the expected ratio of 2 heterozygous breeding (dihybrid)
9:3:3:1
What is epistasis?
The allele of one gene affects the expression of another. Epistasis reduces the number of possible phenotypes
What is sex-linkage?
Any gene that is carried on either X or Y chromosome is said to be sex-linked
