Study Guide: Chapter 3 and 4
TEST Tuesday 11/03/15
Mendelian and non-Mendelian Inheritance, Punnett Squares, Pedigree Analysis, and Chi-Square.
Be able to CREATE and DESCRIBE MONOHYBRID and DIHYBRID crosses, including genotype and phenotype ratios.
Be able to INDEPENDENTLY ASSORT alleles for a TRIHYBRID cross (no test cross).
Know your VOCABULARY for BOTH chapters!
That which is inherited and expressed from generation to generation CHARACTERISTIC/TRAIT
Options of a trait that are present in a diploid organism UNIT FACTORS/ALLELES
Contains the information for creating proteins GENE
The separation of sister chromatids during meiosis that separates alleles to create haploid cells SEGREGATION
Physical expression of a gene; what you see PHENOTYPE
What is coded in the DNA GENOTYPE
The inheritance of identical alleles for a trait (HH, hh) HOMOZYGOUS
The inheritance of 2 different alleles for a trait (Hh) HETEROZYGOUS
The expression of type O blood when the A or B allele is present BOMBAY PHENOTYPE
The joint expression of BOTH alleles in a heterozygote CODOMINANCE
Expression of one gene or gene pair modifies the expression of another gene EPISTASIS
The theory that several genes influence a characteristic GENE INTERACTION
The progressively earlier onset and severity of a disorder from generation to generation GENETIC ANTICIPATION
A condition of males since they do not carry 2 homozygous sex chromosomes HEMIZYGOUS
The intermediate expression of 2 different alleles (pink) INCOMPLETE DOMINANCE
A mutation that results in the death of the organism, usually before they can reproduce LETHAL ALLELE
An offspring's phenotype is under the control of gene products in the egg MATERNAL EFFECT
When 3 or more alleles of the same gene are present that impact the phenotype expression MULTIPLE ALLELES
Allele that results in complete loss of function NULL ALLELE
Extranuclear inheritance through the mitochondrial or chloroplast DNA ORGANELLE HEREDITY
The expression of a single gene has multiple phenotype effects PLEIOTROPY
Expression of genes is influenced by the sex hormone concentration of the individual SEX-INFLUENCED INHERITANCE
The allele that occurs most frequently in a population WILD-TYPE ALLELE
Genes that are inherited on the X chromosome show a unique inheritance pattern X-LINKAGE
Describe Mendel’s Postulates
Unit factors occur in pairs
Dominant/Recessive
Segregation
Independent Assortment – for more than 2 traits
Know the COMMONLY used symbols for Pedigree Analysis
Be able to analyze pedigree chart for mode of inheritance.
Differentiate between INCOMPLETE and CODOMINANCE
Review blood group inheritance and be able to solve problems related to blood group inheritance.
ABO: Gene found on chromosome #9; 3 alleles present; A and B are codominant to each other but dominant to
the O allele which is recessive.
MN: Gene found on chromosome #4; M and N are codominant to each other.
Rh Factor: Gene found on chromosome #4; Rh+ is dominant, Rh- is recessive
Be able to describe the significant inheritance pattern for the following human conditions:
Tay-Sach’s Disease: late onset – early childhood; lethal
Huntington Disease: late onset – middle age; lethal
Duchenne muscular dystrophy: late onset – symptoms begin in childhood; lethal
Lesch-Nyhan syndrome: late onset – symptoms begin in early childhood; not lethal
Color blindness: sex-linked
Male pattern baldness: sex-influenced due to hormonal influence
MERRF: mitochondrial (organelle) heredity
Describe the issues surrounding sex-linked (X-linkage) inheritance in human males: Because males only inherit a single X
chromosome, inheriting a single defective copy allows the gene to be expressed where females require 2 copies of the
recessive allele to be affected by the gene
Describe the significance of mitochondrial DNA in term of human disease and inheritance.
How is mtDNA passed from parents to offspring? From mother to all her children. Females contribute
mitochondria to all offspring through the fertilized egg.
Why is mtDNA vulnerable to mutations? Lacks proofreading enzymes to correct mistakes, lacks the nuclear
membrane to limit exposure to mutagens, found in the cytosol where a high level of mutagens can be found.
What VITAL biochemical process is faulty when mutations occur in mtDNA? Aerobic cellular respiration, mainly
the Kreb’s Cycle and ETC
Practice
1.
In rabbits, white fur color (W) is dominant to black, and long ears (L) are dominant to short. Draw a Punnett
square that represents the cross between two rabbits heterozygous for both traits. What are the phenotype and
genotype ratios?
WwLl x WwLl
Assorted gametes = WL Wl wL wl
WL
Wl
wL
wl
WL
WWLL
WWLl
WwLL
WwLl
Wl
WWLl
WWll
WwLl
Wwll
wL
WwLL
WwLl
wwLl
wwLl
wl
WwLl
Wwll
wwLl
wwll