mendelian genetics how genes work. who are you? phenotype – how you look; physical appearance...
TRANSCRIPT
![Page 1: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/1.jpg)
Mendelian GeneticsMendelian Genetics
How Genes Work
![Page 2: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/2.jpg)
![Page 3: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/3.jpg)
Who Are You?Who Are You?
Phenotype–How you
look; PHysical appearance
Genotype–Your genetic
makeup; GENEs
![Page 4: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/4.jpg)
Modern genetics began with Gregor Mendel’s quantitative experiments with pea plants
Father of GeneticsFather of Genetics
Figure 9.2A, B
Stamen
Carpel
![Page 5: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/5.jpg)
Mendel crossed pea plants that differed in certain characteristics and traced the traits from generation to generation
Figure 9.2C
This illustration shows his technique for cross-fertilization
1 Removed stamensfrom purple flower
White
Stamens
Carpel
PurplePARENTS(P)
OFF-SPRING
(F1)
2 Transferred pollen from stamens of white flower to carpel of purple flower
3 Pollinated carpel matured into pod
4 Planted seeds from pod
![Page 6: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/6.jpg)
Genetics BasicsGenetics BasicsChromosomes occur in pairs, one from
MOM, one from DAD (homologues)Genes are carried on chromosomes Genes code for a trait or characteristic
(I.e. hair color)Alternate forms of that trait are called
ALLELES (ie. Blond, brown, redhead, etc)
![Page 7: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/7.jpg)
Alleles…Alleles…
Alleles can be dominant or recessive
Heterozygous vs. homozygousOnly way to “see” a recessive
trait?
![Page 8: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/8.jpg)
Mendel ‘s Mendel ‘s basic lawsbasic laws
Law of Segregation
Law of Independent Assortment
![Page 9: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/9.jpg)
The chromosomal basis of Mendel’s principles
Figure 9.17
![Page 10: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/10.jpg)
Walter Sutton’s Theory of Walter Sutton’s Theory of Chromosomal InheritanceChromosomal Inheritance
(Mendel’s proof)(Mendel’s proof)Gametes contribute to heredity via
nuclear material (chromosomes)Homologues segregate during
meiosisHomologues separate
independently of other homologous pairs
![Page 11: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/11.jpg)
ProbabilityProbability
Mathmatical model of how often specific events will happen
# of occurances/# of attempts
![Page 12: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/12.jpg)
Punnett SquarePunnett Square
Visual representation or model of – what alleles can be present in
gametes – how those alleles can recombine in
offspringUsed to determine the probability of
offspring’s genetic makeup
![Page 13: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/13.jpg)
Monohybrid CrossMonohybrid Cross
One gene–2 alleles considered (one from
mom, one from dad
![Page 14: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/14.jpg)
Dihybrid CrossDihybrid Cross
2 genes–4 alleles considered
![Page 15: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/15.jpg)
![Page 16: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/16.jpg)
How can we determine Homo- How can we determine Homo- vs. heterozygous individuals?vs. heterozygous individuals?
Test Cross–Must use homo recessive to
conduct cross in order to “see” the questionable allele
![Page 17: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/17.jpg)
What Mendel Didn’t SeeWhat Mendel Didn’t SeeMultiple allelesCodominanceEpistasisPolygenic traits or Continuous VariationPleiotropyIncomplete Dominance or “blended
inheritance”Environmental EffectsSex linked and sex influenced traits
![Page 18: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/18.jpg)
CoDominanceCoDominance–Both alleles expressed at the
same time; both dominant
![Page 19: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/19.jpg)
Incomplete dominance: neither allele is fully dominant (blended inheritance)
Figure 9.12Ax
![Page 20: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/20.jpg)
EpistasisEpistasis Sequential action of genes
– Product of one gene influences another (one gene gives “permission” for another allele to work
– Gene action acts as a biochemical pathway & feedback inhibition
Ex: Indian corn coloration
![Page 21: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/21.jpg)
PleiotropyPleiotropy
Where one allele may have multiple effects on phenotype–
![Page 22: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/22.jpg)
Normal and sickle red blood cells
Figure 9.14x1
![Page 23: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/23.jpg)
Individual homozygousfor sickle-cell allele
Sickle-cell (abnormal) hemoglobin
Abnormal hemoglobin crystallizes,causing red blood cells to become sickle-shaped
Sickle cells
Breakdown of red blood cells
Clumping of cells and clogging of
small blood vessels
Accumulation ofsickled cells in spleen
AnemiaHeart failure
Pain and fever Brain
damageDamage to
other organs
Spleen damage
Kidney failure
RheumatismPneumonia and other infections
Paralysis
Impaired mental
function
Physical weakness
![Page 24: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/24.jpg)
Continuous VariationContinuous Variationor Polygenic Traitsor Polygenic Traits
Multiple genes acting to influence a characteristic–Produces gradual changes, not
distinct “borders”Ie. Height, weight, nose length, skin pigment
![Page 25: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/25.jpg)
Figure 9.16
P GENERATION
F1 GENERATION
F2 GENERATION
aabbcc(very light)
AABBCC(very dark)
AaBbCc AaBbCc
Sperm
Fra
cti
on
of
po
pu
lati
on
Skin pigmentation
![Page 26: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/26.jpg)
Environmental InfluenceEnvironmental Influence
Example = color change of fur in arctic animals
![Page 27: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/27.jpg)
Same eyes, different lighting Same eyes, different lighting
![Page 28: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/28.jpg)
Multiple AllelesMultiple Alleles
More than one allele per gene
![Page 29: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/29.jpg)
3 alleles (ABO)– 4 phenotypes (A, B, AB, O)
Uses concept of glycoproteins (sugar name tags or antigens) to mark cells
Non-recognition of the correct “name tag” for blood type can cause agglutination
![Page 30: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/30.jpg)
Landsteiner Blood GroupsLandsteiner Blood GroupsType A – galactosamine – AA
(homo) or AO (hetero)Type B – galactose – BB or BOType AB – galactosamine +
galactose (codominant)Type O – no sugar marker - OO
![Page 31: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/31.jpg)
Blood Donor FactsBlood Donor Facts
Universal Donor Universal Recipient
![Page 32: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/32.jpg)
Rh factorRh factorRh factor can be + or –+ is like a “seen” name tag or antigen - is “invisible”Rh- moms that have Rh+ babies are subject
to spontaneous abortions – Erythroblastosis fetalis
– Controlled with an injectionof RhoGam to “hide” babies cells
![Page 33: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/33.jpg)
Sex LinkedSex Linked “Sex on the X” Specific
trait/disorder is found on sex chromosome, usually the X
Usually recessive traits
Seen more often in males than females
Ex: color blindness, hemophilia
![Page 34: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/34.jpg)
![Page 35: Mendelian Genetics How Genes Work. Who Are You? Phenotype – How you look; PHysical appearance Genotype – Your genetic makeup; GENEs](https://reader030.vdocuments.net/reader030/viewer/2022032607/56649ece5503460f94bdabd4/html5/thumbnails/35.jpg)
Barr Body inactivationBarr Body inactivation
In females, both X chromosomes are not metabolically active
Random inactivation of one X chromosome may influence traits expressed