Genetics. Study of inheritance, the stability and variance of inheritance patterns Gregor Mendel, “The Father of Genetics” Worked with the garden pea plant using cross pollination What would happen if we all had the exact same DNA sequences? What if we had extremely divergent DNA sequences?
True or False: The phenotype of an organism is dictated by the genotype of that organism
If an organism has the genotype BB, how many different gametes can it make? 1: B
When predicting gametes, keep in mind that each gamete must have 1 complete set of instructions
Cc DDEE GgHh
2: C, c 1: DE 4: GH, Gh, gH, gh
KKLlMM TTUUVV AaBBCc
2 1 4
Crossed a true breed purple flower plant with a true breed white flower plant
P generation PP x pp P-purple
F1 generation, all purple heterozygous dominant
Crossed the F1 generation with each other
Pp x Pp
F2 generation PP, Pp, Pp, pp
Genotypic Ratio 1 PP: 2 Pp :1 pp
Phenotypic Ratio 3 purple: 1 white
Cross a heterozygous dominant blue feathered parrot with a yellow feathered parrot
Genotypic ratio 1 Bb : 1 bb
Phenotypic ratio 1 Blue : 1 yellow
Genotypic Ratio 1 HH: 2 Hh : 1 hh
Phenotypic Ratio 3 with horns : 1 no horn
P generation AABB x aabb
F2 AaBb x AaBb
4 by 4 punnett square
Phenotypic ratio 9 purple, tall: 3 purple, short: 3 white, tall: 1 white, short
A Independent Assortment
In panthers, black fur is dominant to yellow fur.
A recessive gene results in the absence of claws.
Predict the offspring of a cross between a heterozygous black panther with no claws and a yellow panther that is heterozygous for claws
B-black fur b-yellow fur
C-claws c-no claws
Genotypic Ratio 1:1:1:1
Phenotypic Ratio 1:1:1:1
PP or Pp
PP x pp = all offspring are Pp (purple)
Pp x pp = ½ offspring are Pp (purple)
½ offspring are pp (white)
F-normal, no cystic fibrosis f-cystic fibrosis Independent Assortment
What are the chances of offspring from 2 heterozygote parents for the cystic fibrosis gene having the disease?
Parents are carriers
25% (1 out of 4) will have cystic fibrosis
What are the genotypic/phenotypic ratios?
P-polydactyly (extra fingers/toes) p-normal
What are the chances of offspring from a cross of 2 heterozygous parents for polydactyly also having the condition?
75% (3 out of 4) chance of having polydactyly
What is the genotypic/phenotypic ratios?
Genotypic Ratio 1 AO : 1 BO
Phenotypic Ratio 1 Type A : 1 Type B
Type B blood male and a Type O blood female never produce a Type O blood child.
Is this possible? Why or why not?
Type B blood can be BB or BO*
Genotypic Ratio All are BO
Phenotypic Ratio All are Type B
*this genotype would produce a Type O offspring
If father’s genotype is BO, it would be possible to get an O blood type child
Genotypic ratio: 1 BO: 1 OO
Phenotypic ratio: 1 type B: 1 type O blood
R-red r-white Rr-pink
S-no sickle cell s-sickle cell (recessive)
Cross 2 heterozygous dominant parents together.
How many children would have sickle cell?
How many children would not?
How many children are resistant to malaria? How many are not?
Parents are Ss-do not have sickle cell
3 children do not have sickle cell, 1 does
3 children protected, 1 is not
Ex. Labrador fur color
Female-Cc not colorblind Colorblind male-c
But CB is X-linked XCXc XcY
Female offspring ratio 1 CB: 1 no CB
Male offspring ratio 1 CB: 1 no CB
M-no MS m-has MS
No, all male offspring would have MS
H-no Hemophilia h-Hemophilia Alleles
Yes, female offspring would not have hemophilia, but are carriers for the gene