Complex Inheritance
and
Human Heredity
Chapter 11
Inheritance
and
Heredity
Section One
Recessive Genetics Disorders
• A recessive trait is expressed when an individual is
homozygous for the trait
Dominant Genetic Disorders
Pedigrees
• A diagram that traces the inheritance of a particular
trait through several generations
Inferring Genotypes
• Knowing physical traits can help determine
what genes an individual is most likely to have
Predicting Disorders
• Recordkeeping helps scientists use pedigree
analysis to study inheritance patterns,
determine phenotypes, and ascertain
genotypes
Genetic Disease Worksheet
• Use the tables on pages 297 and 298
• Fill in ALL the information for each disorder
• Turn in to your name folder when finished
Complex Patterns
of Inheritance
Section Two
Incomplete Dominance
• The heterozygous phenotype is an intermediate
phenotype between the two homozygous
phenotypes
• Both alleles are expressed in the heterozygous
condition
Sickle Cell Disease
• 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
Multiple Alleles
• Rabbit Body Color (coded for
by four alleles)
Chinchilla
https://courses.lumenlearning.com/bio1/chapter/reading-multiple-alleles/
Light gray
Dark gray
Himalayan
Albino
Multiple Alleles
• Blood Type: ABO
blood groups have
three forms of alleles
Sex Determination
• Sex chromosomes
determine an individual’s
gender
• XX is female, XY is male
• X chromosome carries
genes necessary for both
male and female
development
• Y chromosome carries
mainly genes needed to
develop male
characteristics
Sex-Linked Traits
• Genes located on the X-chromosome
• Red-Green Colorblindness
• Hemophilia
Polygenic Traits
• Arise from the interaction of multiple pairs of genes
Environmental Influences
• Environmental Factors
• Diet and Exercise
• Sunlight and water
• Temperature
Twin studies
• Helps scientists separate
biological contributions from
environmental ones
• Traits that appear frequently
in identical twins are at least
partially controlled by
heredity
• Traits expressed differently
in identical twins are strongly
influenced by environment
http://thedailymanila.com/2016/06/07/3-facts-twins-dont-know/
Chromosomes
and
Human Heredity
Section Three
Karyotype Studies
• Karyotype: micrograph in which
the pairs of homologous
chromosomes are arranged in
decreasing size
• Chromosomes are stained during
http://www.getmededu.com/karyotype.html
metaphase
• Chromosomes are arranged in
decreasing size to produce a
micrograph
https://en.wikipedia.org/wiki/Karyotype
Nondisjunction
• Cell division during which sister chromatids fail to
separate properly
• Down Syndrome
• Have a full or partial copy of chromosome 21
Pedigree Tables Practice Problems
• Groups of 2
• Work together to answer the pedigree problems
• Turn in one answer sheet with both names on it
• DO NOT WRITE ON THE HANDOUT
Chapter 11 Assessment Problems
• Pg. 319-321
• 1-3
•6
• 10-15
• 17
• 21-23
• 25-26
• 30
Intro to Chapter 12: Molecular Genetics
https://www.youtube.com/watch?v=_POdWsii7AI