Chapter 10 Flashcards
What is the blending theory of inheritance?
Is it still used?
Suggested that hereditary traits blend evenly in offspring through mixing of the parents blood
No, scientists used it up until the 1900s
How did Mendel prevent peas from self pollinating and how did he cross pollinate them
To prevent them from self fertilizing he cut off their anthers so they had to get pollen from their plants
He cross pollinated by using pollen from other plants to fertilize
What is the P Generation? F1 Generation? F2 Generation?
P- the plants used in the initial cross that produce the F1 Gen
F1- the first generation of offspring from the initial cross
F2- the result of the F1 generation crossing itself
What was Mendels first hypothesis?
The adult plants carry a pair of factors that govern the inheritance of each character
These factors are known as genes
What’s Mendels second hypothesis?
If an individuals pair of genes consists of different alleles, one allele is dominant over the other, recessive allele
What is Mendels third hypothesis?
What principle is this?
The pairs of alleles that control a character segregate (separate) as gametes are formed; half the gametes carry one allele while half carry the other
The principle of Segregation!!
What is a monohybrid cross?
A cross between two individuals that contain the same pair of alleles for a given trait
Ex: Pp x Pp
PP x pp
What’s the difference between genotype and phenotype?
Genotype- genetic constitution of an organism (the letters of the alleles)
Phenotype- outward appearance (physical appearance)
What is the product rule in probability?
If you have a probability of A and a probability of B and you want to find the probability of them happening right after each other then you multiply the probability of A by the probability of B
What is the sum rule in probability?
When several different events all can give the same outcome, you add the probabilities of each outcome together.
What is a dihybrid cross?
A cross between two individuals that are heterozygous for two pairs of alleles
What is Mendel’s fourth hypothesis he discovered after dihybrid crosses?
What principle did this lead to?
The alleles of the genes that govern the two characters segregate independently during formation of gametes.
The principle of independent assortment
Who drew the parallel between genes and chromosomes and what theory was formed?
Walter Sutton used Mendels work to tie genes to chromosomes and formed the chromosome theory of inheritance
What is the locus?
The particular site on a chromosome where a gene is located
It is a particular DNA sequence that encodes a protein or RNA product responsible for the phenotype controlled by the gene
Why did Mendel choose the pea for his tests?
- it could be gown easily in the garden
- gametes are produced in the structures of the flowers
What is incomplete dominance?
Example?
It occurs when the effects of recessive alleles can be detected to some extent in heterozygotes
Ex: flower colour in snapdragons
What is codominance?
Example?
Occurs when alleles have approximately equal effects on individuals
Makes two alleles equally detectable in heterozygous
Ex: inheritance of blood types
Red cow and white cow make roan cow
Can you distinguish between codominance and incomplete dominance by comparing the ratio of offspring of the two?
No
What are multiple alleles?
Examples?
More than two different alleles for a gene
Ex: ABO blood group
What is epistasis?
Genes interact with one or more alleles of a gene at one locus inhibiting or masking the effects of one or more alleles of a gene at a different locus
What is polygenic inheritance?
Several to many different genes contribute to the same character
What is pleiotropy?
Single genes affecting more than one character of an organism
Difference between characters and traits?
Characters- heritable characteristics such as flower colour or seed shape
Trait- a variation in character, such purple or white flower
