Causes of mutation

Antibiotic resistance

Types of Mutation

Mutation

Species variation

Pedigree diagrams

3.20a Understand how to interpret family pedigrees

3.20b

Genetic probabilities

3.21b Predict the probabilities of outcomes from mono hybrid crosses

F1 cross.

Between an F1 offspring crossed with an F1 offspring.

The parent phenotype is a red petal crossed with a red petal and the parent genotype is Rr x Rr the heterozygotes.

meiosis: The alleles need to be separated one into each type of gamete.
Half of the pollen grains would be R and the other half would be r.

Genotype offspring: RR : 2Rr : rr

These are probabilitties or chances not numbers.

Phenotype ratio (F2)   Red : Red : White

       3:1 ratio    75% red and 25% white.

These are just chances.

Genetic Probabilities

3.21a predict probabilities of outcomes from monohybrid crosses.

Monohybrid means 1 gene and so 2 alleles.

Parents:                              red              x             White petal
Genotype:                          RR              x              rr                        (R>r)
Meiosis: The gamete will contains only 1 of the 2 alleles. It has an equal chance.
1/2R and 1/2R   with     1/2r and 1/2 r

Random fertilization: eg



The genotype of the offspring is Rr

This means that the phenotype offspring is all RED.(100%)

Codiminance

3.18c recall the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and codominance