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Will I need therapy after this class?. Lecture 14 - Genetics. Mendel Founder of modern genetics called classical genetics or Mendelian genetics.

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Will I need therapy after this class?

Lecture 14 - Genetics


Mendel Founder of modern genetics called classical genetics or Mendelian genetics

http://images.google.com/imgres?imgurl=eesc.orst.edu/agcomwebfile/magazine/99Spring/Images/mendel!.gif.gif&imgrefurl=http://eesc.orst.edu/agcomwebfile/magazine/99Spring/OAPSpring99text/OAPSPRG9906.html&h=172&w=198&prev=/images%3Fq%3DMendel%26start%3D40%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DN


Mendel’s garden in Austria

http://images.google.com/imgres?imgurl=nitro.biosci.arizona.edu/courses/EEB320/Lecture03/pics/medgard.jpeg&imgrefurl=http://nitro.biosci.arizona.edu/courses/EEB320/Lecture03/Lecture03.html&h=284&w=384&prev=/images%3Fq%3DMendel%2527%2Bgarden%26start%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DN


Mendel (Genetics) vs (?) Darwin (Evolution)

Worked in mid 1800s

Saw work of the other as contradictory to their own work

Mendel’s work now explains Darwin’s work


Mendel studied inheritance of garden pea anatomy and described meiosis without knowing anything about meiosis


........such as shape, color and texture of pea seeds.


Morgan advanced Mendel’s ideas using fruit flies.

http://images.google.com/imgres?imgurl=www.amphilsoc.org/library/images/genetics/morgan2.jpg&imgrefurl=http://www.amphilsoc.org/library/guides/genetics.htm&h=329&w=300&prev=/images%3Fq%3Dmorgan%2Bgenetics%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8


Next………………………………

Some genetics terms and concepts


Gene = that section of DNA responsible for trait (seed color, eye color, skin color, etc.)

Chromatin

Gene


Genes

Genes make protein products

Alleles are alternate forms of gene for same trait

Hemoglobin normal gene = H

Hemoglobin sickle cell gene = h(allele)


Genotype

Genotype is combination of genes responsible for traits or products.

Three possibilities for genes H and h:

HHand hhand Hh

HH and hh = Homozygous Genotypes

Homo = same zygous = union;

Hh = Heterozygous Genotype

Hetero = other zygous = union


Egg

sperm

H

H

h

h

HH

Homozygous genotypes

hh

Normal zygote

h

H

zygote with sickel cell

Heterozygous genotype

Hh

Normal zygote


Phenotype

Physical, chemical, physiological, behavioral appearance of organism


Review - Gene, Genotype & Phenotype

Phenotype = normal red blood cell

PHENOTYPE = normal hemoglobin

GENOTYPES = HH or Hh

H = normal hemoglobin GENE

h = abnormal hemoglobin GENE

PHENOTYPE = abnormal hemoglobin

Phenotype = sickled red blood cell

GENEOTYPE = hh


Types of genetic interactions following amphimixis:

Dominance / recessiveness

Incomplete Dominance

Codominance

Pleiotropy

Atavism

Multiple Alleles at the same loci


Dominant / Recessive Alleles

Dominant allele - homozygous or heterozygous genotype = same phenotype

Recessive allele – phenotype only shows up in homozygous genotype

AllelesGenotypesPhenotypes

T (tall plant)TTTall Plant

t (short plant)TtTall Plant

ttShort Plant


G = allele for green seed pods is dominant g = allele for yellow pods is recessive

gg GG or Gg


Polydactyly due to dominant gene (P); normal is due to recessive allele (p)

PP or Pp genotype

syndactyly

pp is normal

PP or Pp


Attached and Free earlobes

Genotypes ff FF or Ff

Phenotypes attached Free


Several types of interactions:

Dominance / recessiveness

Incomplete Dominance

Codominance

Pleiotropy

Atavism

Multiple Alleles at the same loci


Incomplete Dominance

neither allele is completely expressed when the other allele is present.

GenesGenotypesPhenotypes

R (red flower)RRRed

W (white flower)WWWhite

RWPink

WW RWRR


Several types of interactions:

Dominance / recessiveness

Incomplete Dominance

Codominance

Pleiotropy

Atavism

Multiple Alleles at the same loci


Codominance

equal expression of two alleles that occur at the same loci on homologous chromosomes

GenesGenotypesPhenotypes

IAIAIABlood type A IBIBIBBlood type B iiiBlood type O IAIBBlood type AB IAiBlood type A IBiBlood type B

IA and IB are codominant to each other, but dominant to i


Type “A” protein in membrane

Type A blood is IAIA or IAi

Type “B” protein in membrane

Type B blood is IBIB or IBi

Type “A” and type “B” proteins in membrane

Type AB blood is IAIB

Neiter Type “A” or type “B” proteins in membrane

Type O blood is ii


Several types of interactions:

Dominance / recessiveness

Incomplete Dominance

Codominance

Pleiotropy

Atavism

Multiple Alleles at the same loci


Pleiotropy = single gene has have multiple effects


Bad hemoglobin protein = bad cells


Bad cells = bad physiology


Bad physiology = organ failures and “bad” life

Key word is ……BAD


Several types of interactions:

Dominance / recessiveness

Incomplete Dominance

Codominance

Pleiotropy

Atavism

Multiple Alleles at the same loci


Atavism

Traits similar to ancestral evolutionary traits.

Examples include:

human tail, mammary line, human gill slits

May be due to:

ancient genes

mutations resulting in traits that resemble ancient traits


Human gene pool

Normal allele is N

atavistic allele is W and rare

NN = normal

NW = normal

WW = atavism

N

N

N

W

W

N

N

N

N

N

W

N

N

N

N


Human Tail is an example of Atavism or a form similar to an ancestral form


Mammary line - atavistic trait resulting in multiple mammary glands in humans; as is found in other more primitive mammals


There have been some documented cases of humans born with gill slits in neck without gills – very controversial little agreement on origin.


Several types of interactions:

Dominance / recessiveness

Incomplete Dominance

Codominance

Lethal Alleles

Pleiotropy

Multiple Alleles at the same loci


Si

S

Sp

Sw

least

Order of dominance

S – solid black

Si – Black with some white

Sp – white with some black

Sw = all white

Alleles

Black and white coat color in dogs.

Multiple Alleles at the same loci.

3 or more alleles at same loci within a population.

Genotypes

and

Phenotype


genotypes

S S

or

S Si

or

S Sp

or

S Sw

phenotype

S – solid black

Si – Black with some white

Sp – white with some black

Sw = all white


Phenotype = Black with some white

genotypes

Si Si

or

Si Sp

or

Si Sw

S – solid black

Si – Black with some white

Sp – white with some black

Sw = all white


genotypes

Sp Sp

or

Sp Sw

S – solid black

Si – Black with some white

Sp – white with some black

Sw = all white

Phenotype = White with some black


S – solid black

Si – Black with some white

Sp – white with some black

Sw = all white

Sw Sw


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