CHAPTER 3Independent Assortment of Genes

CHAPTER 3Independent Assortment of Genes

Copyright 2008 © W H Freeman and Company

CHAPTER OUTLINE3.1 Mendel’s law of independent assortment

3.2 Working with independent assortment

3.3 The chromosomal basis of independent assortment

3.4 Polygenic inheritance

3.5 Organelle genes: inheritance independent of the nucleus

Mendel’s law of independent assortment- different pairs assort independently in gamete formation

Figure 3-2

Round and wrinkled phenotypes

Figure 3-3

Mendel’s breeding program that produced a 9 : 3 : 3 : 1 ratio

Figure 3-4

Punnett square illustrating the genotypes underlying a 9 : 3 : 3 : 1

ratio

Working with independent assortment

Table 3-1

Generally, a hypothesis is rejected as false if there is a probability of less than 5% of observinga deviation from expectations at least as large as the one actually observed. In other words, thereis a less than 5% probability that the deviation between the observed and expected values is becauseof chance.

The chromosomal basis of independent assortment

Figure 3-7

Different chromosomes segregate independently

Figure 3-8

Independent assortment of chromosomes at meiosis explainsMendel’s ratio

Figure 3-8 part 1

Independent assortment of chromosomes at meiosis explainsMendel’s ratio

Figure 3-8 part 2

Independent assortment of chromosomes at meiosis explainsMendel’s ratio

Figure 3-9

Stages of a Neurospora cross

Figure 3-10a

The linear meiosis of Neurospora

Figure 3-10b

The linear meiosis of Neurospora

Figure 3-11

Recombinants are meiotic output different from meiotic input

Figure 3-12

In diploids, recombinants are best detected in a testcross

Figure 3-13

Independent assortment produces 50 percent recombinants

Polygenic inheritance

Figure 3-14

Continuous variation in a natural population

Figure 3-15

Polygenes in progeny of a dihybrid self

Figure 3-16

Histogram of polygenes from a dihybrid self

Figure 3-17

Histogram of polygenes from a trihybrid self

Organelle genes: inheritance independent of the nucleus

Figure 3-18

Cell showing nucleoids within mitochondria

Figure 3-19

Organelle genomes

Figure 3-20a

Maternal inheritance of mitochondrial mutant phenotype poky

Figure 3-20b

Maternal inheritance of mitochondrial mutant phenotype poky

Figure 3-21

Variegated leaves caused by a mutation in cpDNA

Figure 3-22

Crosses using flowers from a variegated plant

Figure 3-23

Model for cytoplasmic segregation

Figure 3-24

Sites of mtDNA mutations in certain human diseases

Figure 3-25

Pedigree of a mitochondrial disease