Inheritance Patterns
__________________________________________
Introduction
> Genetics in 17th and 18th Centuries:
¤ Many scientists in the 17th and 18th centuries considered heredity to be the
consequence of growth in the womb of a miniature, fully formed individual
contained in the sperm (_____________).§ For Example:
» [Figure 7.1: A Homonculus, Transparency]
Modern Genetics
(Gr. Gennan = to _________)
> Genetics is the study (science) of the transmission of biological information
(____) from one generation to the next.
> Genetics reveals the processes and mechanisms of how ____________ is expressed in an organism.
> The Father of modern genetics is Gregor _________ (1822-1884) where he
1. explained why offspring were _________ or _________; and,2. helped explain how species "_________" or evolve.
Gregor Mendel
> Mendel was born in the Czech Republic;
1. was son of a _________; and,
2. entered Augustinian Monastery in Brunn.
> Mendel did graduate work at the University of Vienna, studing _______, _______ and natural science in 1854.
> In 1857, Mendel started experiments with common garden ______ (Pisum sativum) using a
Unique Approach where he:
1. controlled ___________ of peas;
2. selected "__" clearly defined traits; and,
3. used "_________" between many generations and designed studies through
mathematics.
> Mendel published results of his work in genetics research in _______, in a little known scientific journal,
but not recognized until 1900...
New Age of Genetics (1900 ---)
> Modern Genetics supports Biotechnology or Gene Technologies with benefits in:
1. Mass production of hormones and ___________;
2. increased _____________ production; and,
3. _______ therapy (replacement);
4. using Genetic Engineered Organisms, i.e. __________ and yeast
Genetically Engineered Organisms
> Society must deal with ethical questions of Genetic Engineering:
1. ________ _________;
2. ______ manipulation (humans?);
3. Environmental effects; and,
4. ____________.
See the Genetic Engineering link to the www: http://www.kadets.d20.co.edu/~lundberg/paper.htmlWhat "NEW" web links dealing with genetics can you locate on the www?
Segregation of Genes
> Mendel's Law of __________ _____________.
> States that when gametes are formed (______ / ______), units of inheritance in each parent
are grouped into separate gametes... units known as __________.
(Gr genos = ______)
> Gene Segregation (Mendel's Law of ) : "States that Pairs of hereditary factors (genes) are distributed between ________ when formed."
Problem: If: The "Principle of Gene Segregation" provides a mechanism for inheritable traits
to be distributed (as _______ located at specific positions on members of _________
____________ ) in ___________ ____________.
Then: Gametes (each having at least ____ gene for each inheritable trait)use during fertilization via a process of "___________ ___________" of gametes that
brings the ______ of _____________ ____________ back together.
§ For Example:
» Mendel's First Law of Segragation (equal segragation)In gametic production, the chromosomes segregate as follows:
ø [Figure: Homologous Chromosomes Carrying Alleles* A and a, Transparency]
A a
Prophase I
AA aa
Metaphase I
AA aa
Telophase I
AA aa
Metaphase II
AA aa
Telophase II
A a
A a
Mendel's Law of Segregation: Pairs of hereditary factors (genes) are
distributed between gametes during gamete formation.
*Allele (Gr alleles = each other) One of a group of alternative forms of a
gene that may that may occur at a given site (locus) on a chromosome.
> In order to show how genes "segregated equally" between ________, Mendel preformed the___________Cross.
¤ The Monohybrid Cross satisfies the requirements of Mendel's First Law
.... the "Law of _______ ___________" of genes when....
For Example:
[Figure: A Monohybrid Cross, Transparency ]
Homozygous
____________ Recessive
Red flowered _______ _______
Parental
Generation P__
Gametes P__
First _______
Generation F_ Heterozygous
Gametes ____
Second _______
____________ F__
____ Red ____ White
> Mendel's Law of Independent ____________.
"States that when in gamete formation, the ___________ of genes determining one trait
does not influence how genes determining a second (or other) trait are distributed."
¤ In order to demonstrate this, Mendel preformed the
Dihybrid Cross
(Gr di = two + hybrid = offspring of two kinds of ________)
§ For Example:
» [Figure: A Dihybrid Cross, Mendel's Law of Independent Assortment, Transparency]
(a')
(b')
Independent Assortment... of members of two gene pairs during gamete
formation in dihybrid individuals.
a' _________________b' _________________
> Using a Matrix to express the _________ __________ with the
Punnett Square
¤ For Example, in the Dihybrid Cross
§ [Figure: Punnett square of Dihybrid Cross, Transparency ]
Phenotypes Smooth yellow Wrinkled green
In summary, Mendel's Second Law reveals a Phenotype ratio of:
___:___:___ = Mendel's Law of ____________ Assortment
Sex Determination in Mammels and Birds
> The Sex _____________.¤ For Example:
§ [Figure: Mammals vs. Birds, Transparency]
Mammals Birds
XX ___ ___ ZZ
Female Male Female Male
Genetic Inheritance of Red Green Color Blindness in Humans
> Color Blindness in humans involves a ______ ________ trait
¤ For Example: § [Figure: Sex-linked trait of Color-Blindness, Transparency]
Wife Husband(normal color vision) (colorblindness)
Multiple Alleles
> Unlike the individual organism (where 2 genes, one on each chromosome), populations of a
given type of organism may have many different alleles or "______ ______" that regulate a ___________.
¤ For example, ABO blood types in humans are regulated by___ alleles ( _____, _____, and _____)Note: the "i" is ___________, and _____ & ______ are neither __________ or recessive to each other....
with ____ and ____ are together, both are __________.
§ For Example:
» [Figure: Synthesis of the A and B blood group antigens, Transparency]
Summary of Antigens and Phenotypes / Gernotypes of ABO Blood Types in Humans
[Table: Antigens and Phenotypes/Genotypes of ABO Blood Types, Transparency, see Text, Table 7.2, pg. 103]
Phenotype Blood Antigens Genotypes O
A
B
AB
Another Multiple Allele
> Rh (factor) blood type:
1. Also regulated via multiple ________ (discovered in WWII).
2. Regulated by 2-alleles with
a. Rh __________ = _____________.
b. Rh __________ = Recessive.(Actually, this system is most complex and involves over _____ alleles expressing the _________.)
Incomplete Dominance and Codominance
> Incomplete dominance results when an interaction between 2-_____ produces a more or less equal
expresssion of the _________... the heterozygote is different from either homozygote.
¤ For example:
Incomplete Dominance
Given:
In cattle, RR = _____ ______R'R' = ______ coat
If:
Parents (P__)... RR X R'R'
(___) (_____)
Gametes... (___) (___) [___'] [___']
F__... ______ Only (___________ Roan)
Backcross:
F__... RR R__' R__' __'__'
(___) (____) (____)
Phenotype... __..........___.......___
Genotype.... __..........___.......___
Heterozygous
___________
Codominance
> Results when the heterozygote experesses the ____________ of both homozygotes.
¤ For Example: The ABO bood type where _______ heterozygotes express both _________.
Also, Sickle Cell Anemia that developed in Africa as a result of a __________ in the genes coded for a protein in ______________,
1. Hb__ = Normal _______ for __________.
2. ____ = _______ ______ allele for hemoglobin.
> Summary of Sicke Cell Codominance
¤ For Example:
§ [Figure: Normal RBCs and Sickle Cell RBCs, Transparency]
Genotypes.... Homozygous Heterozygous
Normal Sickle-cell
Hemoglobin HemoglobinP_............... ____ ____ X ____ ____
G_.............. (__) (__) (__) (__)
F_............... 2 ____ ____ individuale (_____________)
2 ____ ____ individuals (_____________)
Backcross.................. ( Heterozygous X Heterozygous )
P_.............. ____ ____ X ____ ____
G_............. (__) (__) (__) (__)
F_.............. 1 ____ ____ ____________ Normal
2 ____ ____ Heterozygous ________ _____
1 ____ ____ ___________ ________ _____
NOTE: The ____ _____ genotype expression causes severe _________ and usually ________.
However, the _____ _____ genotype gives some protection against _________.
> Summary of Codominance¤ [Table E: Effect of Sickle Allele, Transparency,]
_____________________________________________________________________
Genotype Type of Anemia Resistance
Hemoglobin Present to Malaria
_____________________________________________________________________
_____ / ______ Normal _____ NO
_____ / ______ Normal and ________ _____ Yes
_____ / ______ __________ _____ _____
____________________________________________________________________________________
Quantitative Traits
(Polygenes)
> Many traits display ___________
___________ (color in peas or A and O
blood types),
but other traits change by very
small increments and are
characterized
by a quantitative measure, e.g. weight, height, skin color
and certain
levels of intelligence; displaying continuous
variation over a
range of
__________.
> Traits displaying continuous variation are usually determined by an
interaction of _______
_____, where each loci adds a small increment to
the
_________
expression.
¤ For Example:
[Figure 7.8: How Polygenic Inheritance can Produce Continuous Variation, Transparency, see Text, pg.104]
Example of Quantitative Traits [Height of Humans]
(a) Grandparent 1 Grandparent 2
AABBCC
________
(b) F1 Offspring
_________
(c) Possible Offspring
Environmental Influence on Gene
Expression
> Genetic make up does not always dictate a "blueprint" of the final outcome
of genetic
traits,
For Example: Just as a blueprint for an
engineered building does not represent the finished
structure.
> Many traits
are the outcome of genetic instructions that have been
influenced by
environmental factors,
For Example: X-rays, _______ ______, carcinogens and teratogens, or even temperature, among others,
depending on when in the life history of an organism exposure occurs, and the ______ or
concentration.
> The __________ establishes the more-or-less "fixed potential" for genetic expression... whether realized
or not depends on crucial environmental influences (regulators),
For Example: __________ __________ (animals acquire genetic potential for physical and mental
attributes)