Mendel Invents Genetics Flashcards
What was the proposed mechanism of heredity prior to Mendel?
Blended inheritance
Why are garden peas a good model organism?
Easy to grow Distinct varieties Easy to mate -self-pollinated or cross-pollinated Easy to observe phenotypes
What did Mendel do differently?
Began with pure-breeding strains Counted offspring Noted repeatable ratios Proposed a model to explain ratios Tested his model
What was Mendel’s first experiment?
He used pollen from a white-flowered plant to cross-pollinate a purple-flowered plant
He then self-pollinated the offspring
What is a genetic cross?
An experiment in which males and females of a model organism are mated to produce offspring
How do we talk about generations?
P = parents F1 = first filial F2 = second filial
What are reciprocal crosses?
Genetic crosses in which males of genotype A are crossed to females of genotype B and vice versa
What was Mendel’s second experiment?
A yellow and green seed are crossbred and then the offspring is self-pollinated.
1/4 of those offspring with have only yellow or only green offspring
2/4 of the other offspring will have a mix
What is Mendel’s Model?
Heredity is controlled by genes Genes are in pairs One phenotype is dominant Gametes only have one of each gene pair Equal segregation of genes into gametes Random fertilization
What is Mendel’s first law?
The law of segregation
-the two alleles of a gene separate during gamete formation
What is a punnet square?
A method to predict the outcome of a genetic cross
What was Mendel’s third experiment?
The F1 plants carry two alleles but only one is revealed
The experiment was to cross yellow F1 to pure-breeding green
What was Mendel’s fourth experiment?
9:3:3:1 ratio
two superimposed 3:1 ratios
What was Mendel’s second law?
The law of independent assortment
-genes separate independently of each other during gamete formation
