Download Complex Inheritance and Human Heredity

Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Recessive Genetic Disorders
 A recessive
trait is
expressed
when the
individual is
homozygous
recessive for
the trait.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Cystic Fibrosis
 Affects the mucus-producing glands; body
can’t get rid of mucus
Albinism
 Caused by altered genes, resulting in the
absence of the skin pigment melanin in hair
and eyes
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Tay-Sachs Disease
 Caused by the absence of the enzymes
responsible for breaking down fatty acids
 Fat accumulates in the brain, inflating brain
nerve cells and causing mental deterioration.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Dominant Genetic Disorders
 Huntington’s disease affects the nervous
system.
 Achondroplasia causes small body size and
limbs that are comparatively short.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Pedigrees
 A diagram that traces the inheritance of a
particular trait through several generations
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Predicting Disorders
 Helps scientists in following inheritance
patterns and determining phenotypes and
genotypes.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Incomplete Dominance
 The heterozygous phenotype is an
intermediate phenotype between the two
homozygous phenotypes.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Codominance
 Both alleles are expressed in the
heterozygous condition.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sickle-cell Disease
Normal red blood cell
 Changes in hemoglobin
cause red blood cells to
change to a sickle shape.
 People who are
heterozygous for the trait
have both normal and
sickle-shaped cells.
Sickle cell
7766x
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Multiple Alleles
 Blood groups in
humans
 ABO blood groups
have three forms
of alleles.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Coat Color of Rabbits
 Multiple alleles can demonstrate a hierarchy
of dominance.
 In rabbits, four alleles code for coat color:
C, cch, ch, and c.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Coat Color of Rabbits
Chinchilla
Albino
Light gray
Dark gray
Himalayan
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sex Determination
 Sex chromosomes
determine an
individual’s gender.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sex-Linked Traits
 Genes located on the X chromosome
 Red-green color blindness
 Hemophilia
Sex-Linked
Traits
Chapter 11
Complex Inheritance and Human Heredity
11.3 Chromosomes and Human Heredity
Karyotype Studies
 Karyotype—graph of homologous
chromosomes arranged in decreasing size.