10.1
What Are the Mendelian Laws of Inheritance?
207
Mendel brought new methods to experiments
on inheritance 208
Mendel devised a careful research
plan 208
Mendel’s first experiments involved
monohybrid crosses 209
Alleles are different forms of a gene
211
Mendel’s first law says that
the two copies of a gene segregate
211
Mendel verified his hypothesis by
performing a test cross 213
Mendel’s second law says that
copies of different genes assort independently
213
Punnett squares or probability calculations:
A choice of methods 214
Mendel’s laws can be observed
in human pedigrees 216
10.2
How Do Alleles Interact? 217
New alleles arise by mutation 217
Many genes have multiple alleles 218
Dominance is not always complete 218
In codominance, both alleles at a
locus are expressed 219
Some alleles have multiple phenotypic
effects 219
10.3
How Do Genes Interact? 219
Hybrid vigor results from new gene
combinations and interactions 220
The environment affects gene action
220
Most complex phenotypes are determined
by multiple genes and the environment
221
Genes on the same chromosome are linked
223
Genes can be exchanged between chromatids
223
Geneticists can make maps of chromosomes
224
Linkage is revealed by studies of
the sex chromosomes 225
Genes on sex chromosomes are inherited
in special ways 226
Humans display many sex-linked characters
227
10.5
What Are the Effects of Genes Outside
the Nucleus? 228
