Exam 4 part 6 Flashcards
What does F1 stand for
First filial generation, first generation after parental generation
Describe the meaning of dominant and recessive traits
For a recessiveallele to produce arecessivephenotype, the individual must have two copies, one from each parent. An individual with onedominantand onerecessive allele for agenewill have thedominantphenotype
Describe what a reciprocal cross is
A pair of crosses between a male of one strain and a female of another, and vice versa
What do we now identify as the “particles” in Mendel’s hypothesis of particulate inheritance
genes
What are alleles
different versions of each gene
Do individuals with the same genotype always have the same phenotype? Why or why not
Environmental conditions will cause them to appear different
A gene that has two copies of the same allele is referred to as
homozygous
A gene that has two different alleles is referred to as
heterozygous
dominant alleles always mask recessive alleles when they are paired together.
true
What is the difference between a monohybrid cross and a dihydrid cross
Monohybrid: crossing a single trait (ex: round vs wrinkled)
Dihybrid: crossing two traits (ex: round vs wrinkled AND yellow vs green)
Did Mendel’s experiments support the hypothesis of independent assortment or dependent assortment
Independent assortment
Means that different traits don’t depend on each other
What is a testcross
a parent that is homozygous recessive for a particular trait is mated with a parent that has the dominant phenotype but unknown genotype
While doing a testcross, what are the possible genotypes of the unknown parents
Either heterozygous or homozygous dominant
What is a wild type
The most common phenotype for each trait
Mendel crossed a wrinkled pea pure line to an individual with round peas but an unknown genotype. All of the progeny had round peas. What was the unknown individuals genotype
RR
What is the difference between a mutation and mutant
Mutation: phenotypes that differed from the wild type, results from the change in a gene
Mutants: individuals with traits attributable to mutation
Genes on autosomes are said to show
autosomal inheritance
What is sex-linked inheritance
The pattern of inheritance that may result from a gene located on either the X or Y chromosome
What is the different between sex-linked and linked genes
Sex-linked means that it is on a sex chromosome
Linked genes are often transmitted together during gamete formation
Multiple allelism is when genes have more than two alleles. When more than two two distinct phenotypes are present in a population due to multiple allelism, the trait is called what
polymorphic
What is the difference between incomplete dominance and codominance
Incomplete: The heterozygotes have an intermediate phenotype
Codominance: a heterozygous organism that displays the phenotype of both alleles of a gene
Genes that influence many traits are
pleiotropic
What is the difference between a discrete and quantitative trait
Discrete traits are characteristics that are qualitatively different (ex: green vs yellow, nothing in between)
Quantitative traits are traits that are not discrete but fall into a continuum (ex: height, weight)
What is a pedigree
Family tree used to analyze existing human crosses
Record gender and genetic relationships among individuals in a family
Help reveal patterns of inheritance
Do males or females determine the gender of the zygote
males
