Alles, Genes And Phenotypes Flashcards
What is wild type?
Allele that is common and thought of as the default phenotype
What is a gene with multiple alleles called?
Polymorphic
What is codominance?
Two alleles that produce different phenotypes are both expressed
What is incomplete dominance?
Heterozygotes may have a blended phenotype
What is a pleiotropic Allele?
An Allele that has multiple phenotypic effects
What is epistasis?
Phenotypic expression of one gene is influenced by the products of other genes
What environmental conditions can effect phenotype?
Light
Temperature
Nutrition
Etc
What is penetrance?
Proportion of individuals with a genotype that develop the expected phenotype
What is expressivity?
The degree to which a phenotype is expressed in an individual
What are qualitative traits?
Those that have discrete qualities often controlled by alleles at a single locus
What are quantitative traits?
Show continuous variation, can be included by genes at many locus as well as the environment
Why are Drosophilia model organisms in genetic research?
Small
Easy to breed
Short generation time
Who pioneered a study of Drosophilia?
Thomas Hunt Morgan
What did Morgan discover?
Noticed that not all dihybrid crosses resulted in 9:3:3:1 ratio
Violation of the law of independent assortment is due to gene linkage
Demonstrated that alleles of genes on the same chromosome can be inherited together as they are physically linked
What is recombinant frequencies?
Number of Recombinant offspring divided by total number of offspring
Recombinant frequencies are greater for genes that are farther apart because an exchange event is more likely to occur between genes that are far apart
What can recombinant frequencies be used for?
To inter the location of genes on a chromosome and make up genetic maps
What are the units of genetic distance?
Map units (mu) or centiMorgans (cM)
One mu or cM is equal to a 1% recombinant frequency
What is sex linkage?
Traits that are carried on sex chromosomes
What is the homogametic sex?
Will have two copies of a gene
What is the heterogametic sex?
Will have one copy of the gene
What is hemizygous?
Gene that is present in a single copy in an otherwise diploid individual
