Transcript What do you know about the word genetics?

I can understand simple Mendelian genetic
principles. I can work punnett squares.
• What is the purpose of
mitosis?
• What is the purpose of
meiosis?
• 1. A zygote is a _
• 2. Cell Specialization is __
• 3. As cells differentiate the body changes
shape called: _
• 4. Apoptosis is critical in morphogenesis.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• 1. Take haploid egg out of female.
• 2. Remove haploid nucleus, implant diploid
nucleus of desired organism.
• 3. Place egg in surrogate (recipient ).
• Dolly 1997
I can understand simple Mendelian genetic
principles. I can work punnett squares.
Mammary
cell donor
Egg cell
donor
Egg cell
from ovary
Cultured
mammary cells
are semistarved,
arresting the cell
cycle and causing
dedifferentiation
Nucleus
removed
Cells fused
Nucleus from
mammary cell
Grown in culture
Early embryo
Implanted in uterus
of a third sheep
Surrogate
mother
Embryonic
development
Lamb (“Dolly”) genetically identical
to mammary cell donor
• Embryonic Stem Cells- totipotent-can be
anything
– No genes are locked=can make any gene, protein,
enzyme,
• Adult Stem Cells-pluripotent-can be several
things
– Some genes locked, can be lots of different cells
I can understand simple Mendelian genetic
principles. I can work punnett squares.
Embryonic stem cells
Adult stem cells
Totipotent
cells
Pluripotent
cells
Cultured
stem cells
Different
culture
conditions
Different
types of
differentiated
cells
Liver cells
Nerve cells
Blood cells
• 1. When is DNA replicated in the cell cycle?
• 2. Mitosis = _ divisions of the cell.
• 3. Meiosis = _ divisions of the cell.
MITOSIS
MEIOSIS
Parent cell
(before chromosome replication)
Chiasma (site of
crossing over)
MEIOSIS I
Propase
Prophase I
Chromosome
replication
Duplicated chromosome
(two sister chromatids)
Chromosome
replication
Tetrad formed by
synapsis of homologous
chromosomes
2n = 6
Chromosomes
positioned at the
metaphase plate
Metaphase
Anaphase
Telophase
Sister chromatids
separate during
anaphase
2n
Tetrads
positioned at the
metaphase plate
Homologues
separate
during
anaphase I;
sister
chromatids
remain together
Metaphase I
Anaphase I
Telophase I
Haploid
n=3
Daughter
cells of
meiosis I
2n
MEIOSIS II
Daughter cells
of mitosis
n
n
n
Daughter cells of meiosis II
Sister chromatids separate during anaphase II
n
Figure 9.15 The Human Karyotype
DNA chromatin in Interphase in cell.
Chromosomes have been stained in Metaphase to distinguish
homologous chromsomes.
• As a human you have
46 chromosomes in
your somatic cells.
• 23 from dad, 23 from
mom.
• You only have 23
chromosomes in your
sex cells (egg/sperm).
• Each of the 23
chromosomes inherited
by your parents line up in
pairs.
• These pairs are known as
homologous
chromosomes.
• These homologous
chromosomes are
identical in size, shape,
and location of genes.
• During Prophase I, a process called synapsis/
chiasmata occurs. Homologous chromosomes
pair by adhering at their lengths.
• Proteins aid in this adhesion by forming a scaffold
called a synaptonemal complex.
• The four bound chromatids form a tetrad.
• How many chromatids are in human cells during
Meiosis I?
• 92
Meiosis I
• Homologues will meet and
form a tetrad.
• Crossing over occurs: allele
swapping.
• Telophase I- two new cells
with one homologue per cell
(still replicated chromatids)
Meiosis II
• Prophase, Metaphase and
Anaphase similar to Mitosis and
Meiosis I.
• Telophase II results in four
haploid daughter cells.
• One chromatid per cell
• The chromatids that result are known as
recombinant chromatids
• Not all organisms directly enter Meiosis II.
• If an organism does not, it does form a nuclear
membrane at the end of Telophase I
• Telophase I is followed by interkinesis, which
is similar to mitotic interphase
• Homologues are not identical like in Meiosis I
because of crossing over.
• The result is four haploid nuclei, with a single
set of unreplicated chromosomes.
• Synapsis, crossing over, and segregation of
homologues
• Aneuploidy- when there are either missing or
excessive chromosomes.
– Monosomy
– Trisomy 10-30% human zygotes show trisomy
– Aneuploidy, ~20% of miscarriages due to aneuploidy
(extra or missing chromosomes)
– Polyploidy complete extra sets of chromosomes, can
occur naturally, can be result of genetic engineering
– Aneuploidy Simulations- Utah Site
• Benefits: Quick- good
for takeover
• Pitfalls: Because of no
variety one
parasite/pathogen and
all die.
• Benefits: VARIATION
• Pitfalls: Time, it takes 2,
need opposite sexes,
gametes are harder to
make.
Key
Haploid
Diploid
n
Gametes
n
Mitosis
n
MEIOSIS
Haploid multicellular
organism (gametophyte)
n
2n
Diploid
multicellular
organism
Animals
Zygote
2n
Mitosis
n
n
Spores
n
n
Gametes
FERTILIZATION
MEIOSIS
2n
Diploid
multicellular
organism
(sporophyte)
Mitosis
n
n
Gametes
MEIOSIS
Mitosis
Mitosis
n
n
FERTILIZATION
Haploid multicellular
organism
2n
Mitosis
Plants and some algae
Zygote
FERTILIZATION
2n
Zygote
Most fungi and some protists
n
• Autosomeschromosomes that
codes for all traits
except gender.
– Homologous pairs #1-22
• Sex chromosomeschromosomes that code
for gender.
– Homologous pair #23
– Karyotyping Activity
I can understand simple Mendelian genetic
principles. I can work punnett squares.
Figure 9.15 The Human Karyotype
Where do homologous chromosomes come from?
What phase are these homologous chromosomes next to one another?
All three of these
conditions cause a
form of mental
retardation.
• Known as the Father of
Genetics
• Experimented with pea
plants
• He used “truebreeding” plants which
were self-pollinating.
• These would produce
identical offspring.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Mendel wanted to try
cross-breeding pea
plants.
• Cut off the male parts
(pollen), and dusted
pollen from another
plant to cause
fertilization.aka crosspollination.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
•
•
•
•
•
•
•
Mendel studied seven different traits.
Trait- specific characteristic, like flower color.
P generation- parent generation.
F1 generation- offspring of the P generation.
Traits are controlled by genes.
Genes- segment of DNA
Allele- different forms of a particular gene
– Ex. Hair color, eye color, plant flower color.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• 1. Biological inheritance is determined by
genes passed on from parents to offspring.
• 2. Principle of Dominance- some alleles are
dominant and some are not (recessive).
• Mendel knew that dominant alleles would
always be expressed, and
• Recessive alleles would only be expressed
when the dominant allele was absent, and
there are two recessive copies.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Dominant= capital letter
• Recessive= lower case letter
• If capital letter is present, then that trait is
expressed.
• Must have two lower case letters for trait to
be expressed
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• If (P) = purple, (p)= white what do the
following flowers look like?
• PP = ?
• Pp = ?
• pp = ?
• Study for your quiz tomorrow
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Genotype- gene combinations an individual
possesses
• Phenotype- what an individual looks like
based on genotype
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Heterozygous/ Hybrid: for a particular trait the
individual has one dominant and one
recessive allele. (Tt)
• Homozygous/ Purebreed: for a particular trait
the individual has both dominant or both
recessive alleles. (TT, tt)
I can understand simple Mendelian genetic
principles. I can work punnett squares.
Trait
Phenotype- what you look like
Tongue-Rolling (R)
Free Earlobe (F)
Widow’s Peak (W)
Straight Thumb (N)
Straight Little Finger (S)
Left over Right Thumb Crossing
(L)
Chin Cleft (C)
Mid-digital Hair (H)
Six Fingers (F)
I can understand simple Mendelian genetic
principles. I can work punnett squares.
Genotype- genetic make-up
that makes up phenotype
• Homologous
chromosomes separate
independent of one
another…
• Don’t get all of mom’s
DNA or dad’s DNA
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Just because you have one dominant gene,
does not mean all of your genes are
dominant.
• They are inherited independent of one
another
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• The odds that a
particular event is going
to take place.
• If you flip a coin, there
is a ½ chance that it will
land on heads.
• Apply this concept to
segregation of alleles.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Used to predict possible offspring outcomes.
• Cross one parent with another.
– Tall (TT) x short (tt)
–
–
–
–
Genotypic Ratio:
Phenotypic Ratio:
# of Heterozygous Individuals:
# of Homozygous Individuals:
I can understand simple Mendelian genetic
principles. I can work punnett squares.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• A chart that shows
the phenotypes
for an organism
and all of its
ancestors.
• What is the
difference
between
phenotype and
genotype?
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Squares=males
• Circles=Females
• Each generation is
denoted by a roman
numeral.
• Each individual is
numbered in the
generation
• Blood relations are linked
by vertical lines.
• Marriage relations are
linked by horizontal lines.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Use your Family starting with one set of your
biological grandparents.
• Shade in all circles/squares of brunette
people, and leave blank all other hair colors.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Incomplete Dominancethink of this as a blending
of genes.
• Neither gene is dominant.
• Heterozygous genotype is
a blend of the two alleles.
• Red(RR) + White(WW) =
Pink flower(RW)
• 1:2:1 ratio of offspring
phenotype
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• 1. A cross between a blue blahblah bird & a white blahblah
bird produces offspring that are silver. The color of
blahblah birds is determined by just two alleles.
a) What are the genotypes of the parent blahblah birds in
the original cross?
b) What is/are the genotype(s) of the silver offspring?
c) What would be the phenotypic ratios of offspring
produced by two silver blahblah birds?
• 2. The color of fruit for plant "X" is determined by two
alleles. When two plants with orange fruits are crossed the
following phenotypic ratios are present in the offspring:
25% red fruit, 50% orange fruit, 25% yellow fruit. What are
the genotypes of the parent orange-fruited plants?
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Codominance- both
alleles contribute to the
phenotype.
• Genes do not blend, but
show up distinctly.
• Blood type, calicos,
roan cattle
• Red bull (RR) x White
Cow(WW) = Roan
calf(RW)
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• 1. Predict the phenotypic ratios of offspring when a
homozygous white cow is crossed with a roan bull.
• 2. What should the genotypes & phenotypes for parent
cattle be if a farmer wanted only cattle with red fur?
• 3. A cross between a black cat & a tan cat produces a
tabby pattern (black & tan fur together).
a) What pattern of inheritence does this illustrate?
b) What percent of kittens would have tan fur if a tabby
cat is crossed with a black cat?
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Multiple Alleles- a gene
may have more than
two alleles to code for a
particular trait.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Polygenic Traits- traits
that are controlled by
several different genes.
• Examples include hair
color and skin color,
I can understand simple Mendelian genetic
principles. I can work punnett squares.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
When chromosomes fail to separate
during anaphase of meiosis.
Meiosis is the process that sex cells are
formed.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Trisomy 13 (Patau’s)/18
(Edward’s)- typically die
by 3 months of age
• Trisomy 21- Mental
retardation, facial
distortions.
• Down’s typically occurs in
egg and sperm
production.
• Likelihood of Down’s
occurs with maternal age.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Turner’s Syndrome in
females, results in a
(XO).
• Klinefelter’s Syndrome
in males, results in
(XXY-XXXXY)
I can understand simple Mendelian genetic
principles. I can work punnett squares.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Albinismanimal/person lacks
ability to produce
pigment in hair, skin,
and eyes if they have
two recessive genes for
pigmentation.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Sickle Cell Anemiawhen oxygen levels are
low, blood cells will
form a sickle shape.
• Mostly associated with
African Americans
• Polydactyl- six digit.
Henry VIII had a 6th
finger. (dominant gene)
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Hemophilia- blood is
unable to clot. Queen
Victoria had this, also
affected Czar Nicholas
due to intermarriage.
(inbreeding depression)
• Muscular dystrophychronic muscle wasting
disease.
• Colorblindness- usually
in males.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• Prenatal detection of chromosomal
abnormalities.
• A thin needle is inserted into the amniotic fluid
surrounding the fetus (a term applied to an
unborn baby after the first trimester).
• Cells that are withdrawn have been sloughed off
by the fetus, yet they are still fetal cells and can
be used to determine the state of the fetal
chromosomes, such as Down's Syndrome and the
sex of the baby after a karyotype has been made.
I can understand simple Mendelian genetic
principles. I can work punnett squares.
• 1908 proposed that the frequency of
alleles/genotypes will remain constant if…
• It explains why dominant alleles do not replace
recessive alleles
• 1. A large breeding population
• 2. Random mating- do not chose mates with
certain genotypes (selective mating)
• 3. No mutation of genes (A/a no change, no new
genes)
• 4. No immigration or emigration (no gene flow)
• 5. Natural selection does not affect the survival of
a particular genotype.
• p = the frequency of the dominant allele
q = the frequency of the recessive allele
• For a population in genetic equilibrium:
p + q = 1.0 (The sum of the frequencies of both
alleles is 100%.)
• p2 + 2pq + q2 = 1
• p2 = (% in population homozygous dominant)
2pq = (% in population heterozygous)
q2 = (% in population homozygous recessive)
• H-W Practice Problems
I can understand simple Mendelian genetic
principles. I can work punnett squares.