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.


• 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


Mammary cell donor

Egg cell donor

Cultured mammary cells are semistarved, arresting the cell cycle and causing dedifferentiation

Grown in culture

Egg cell from ovary

Cells fused

Nucleus from mammary cell

Nucleus removed

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


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.

Propase

Duplicated chromosome

(two sister chromatids)

Metaphase

MITOSIS

Parent cell

(before chromosome replication)

MEIOSIS

Chiasma (site of crossing over)

Chromosome replication

2n = 6

Chromosome replication

MEIOSIS I

Prophase I

Tetrad formed by synapsis of homologous chromosomes

Chromosomes positioned at the metaphase plate

Tetrads positioned at the metaphase plate

Metaphase I

Anaphase

Telophase

2n

Daughter cells of mitosis

Sister chromatids separate during anaphase

Homologues separate during anaphase I; sister chromatids remain together

2n

Daughter cells of meiosis I n n

Daughter cells of meiosis II n

Sister chromatids separate during anaphase II n

Anaphase I

Telophase I

Haploid

n = 3

MEIOSIS II

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 Meiosis II

• 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)

• 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

MEIOSIS

Gametes n n

FERTILIZATION

2n

Diploid multicellular organism

Animals

Zygote

2n

Mitosis

Haploid multicellular organism (gametophyte) n

Mitosis n

Spores n Mitosis n

Gametes

MEIOSIS FERTILIZATION n n

Mitosis n

Haploid multicellular organism n Mitosis

Gametes n n

2n

Diploid multicellular organism

(sporophyte)

2n

Mitosis

Plants and some algae

Zygote

MEIOSIS

2n

Zygote

FERTILIZATION

Most fungi and some protists

• Autosomeschromosomes that codes for all traits except gender.

– Homologous pairs #1-22

• Sex chromosomeschromosomes that code for gender.

– Homologous pair #23

– Karyotyping Activity


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.


• 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.


• 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.


• 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.


• 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


• If (P) = purple, (p)= white what do the following flowers look like?

• PP = ?

• Pp = ?

• pp = ?

• Study for your quiz tomorrow


• Genotype- gene combinations an individual possesses

• Phenotype- what an individual looks like based on genotype


• 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)


Trait

Tongue-Rolling (R)

Free Earlobe (F)

Widow’s Peak (W)

Straight Thumb (N)

Straight Little Finger (S)

Phenotype- what you look like

Left over Right Thumb Crossing

(L)

Chin Cleft (C)

Mid-digital Hair (H)

Six Fingers (F)


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


• Just because you have one dominant gene, does not mean all of your genes are dominant.

• They are inherited independent of one another


• 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.


• 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:



• A chart that shows the phenotypes for an organism and all of its ancestors.

• What is the difference between phenotype and genotype?


• 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.


• 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.


• 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


• 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?


• 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)


• 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?


• Multiple Alleles- a gene may have more than two alleles to code for a particular trait.


• Polygenic Traits- traits that are controlled by several different genes.

• Examples include hair color and skin color,



When chromosomes fail to separate during anaphase of meiosis.

Meiosis is the process that sex cells are formed.


• 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.



• Turner’s Syndrome in females, results in a

(XO).

• Klinefelter’s Syndrome in males, results in

(XXY-XXXXY)



• Albinismanimal/person lacks ability to produce pigment in hair, skin, and eyes if they have two recessive genes for pigmentation.


• 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 6 th finger. (dominant gene)


• 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.


• 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.


• 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%.)

•

p 2 + 2pq + q 2 = 1

• p 2 = (% in population homozygous dominant)

2pq = (% in population heterozygous) q 2 = (% in population homozygous recessive)

• H-W Practice Problems


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