Genetics EOC Review

Traits are inherited hair color, flower color, height Give examples of traits hair color, flower color, height Traits are inherited

Traits are controlled by ______ genes Gene is a section of DNA on a chromosome.

Alleles – different versions of a gene Some alleles for hair color are: Brown hair Red hair Blonde hair Black hair

Each trait is controlled by ___________ one from each parent. two alleles These alleles are located on ___________________________ homologous chromosomes homologous chromosomes allele for brown hair allele for blonde hair maternal paternal

Alleles may be dominate or recessive. TRAITS DOMINANT RECESSIVE Flower color purple white Pea color yellow green Pea shape round wrinkled Pod color Plant height tall short

R B M G dominant What type of alleles are is the boss….covers up recessive allele

r b m g recessive What type of alleles are is covered up by dominant allele

rr RR purebred An organism is homozygous for a trait. (both alleles are the same) red red white white rr RR purebred

Rr Tt hybrid An organism is heterozygous for a trait. (both alleles are the different) red tall white short Rr Tt hybrid

phenotype (physical appearance) genotype (genes in DNA…letters)

Which are the phenotypes? Red flower Rr rr Yellow flower

Which are the genotypes? Red flower Rr rr Yellow flower

No dimples is recessive. Dimples is dominant. No dimples is recessive. What is the phenotype of a dd individual? No dimples What is the phenotype of a DD individual? Dimples What is the phenotype of a Dd individual? Dimples

P p p p Heterozygous Purple X Homozygous white Heterozygous purple   p Homozygous white p

P P P p p p p p p p p p Heterozygous Purple X Homozygous white   p p p Drop it like it’s hot!! Homozygous white p p p Slide it to the right!!

P p   Genotypes of the offspring? ________________________ P 50% Pp p 50% pp p p p Phenotypes of the offspring? ________________________________________________ P p p p p 50% Purple 50% White

? G g gg Gg Gg gg Green is dominant to yellow. A hybrid green plant is crossed with a yellow one. What % of the offspring are yellow? gg Gg ? Gg gg X

? Y Yy Yy y In daisies, yellow flower color is dominant to white. You cross a plant with white flowers with a plant heterozygous for yellow flowers. What percent of the offspring would have white flowers? yy Yy yy Yy ? X

If the alleles for the color of a flower are rr , what is true of its parents? The genotype of both parents contained a recessive allele. Rr and Rr or Rr and rr

Bb B b In squirrels, brown fur color is dominant to gray. A male brown squirrel and a female gray squirrel mate. They have both brown babies and gray babies. What is the genotype of the male parent? Bb

T t A tan monkey is mated with a white monkey. All of their offspring are tan. What are the genotypes of the parents? What are the genotypes of the offspring? TT , tt Tt

A red flower is crossed with a white flower. All the offspring are white. Which allele is dominant? white flower Which allele is recessive? red flower What is the genotype of the red flower? ww What is the genotype of the white flower? WW

Rr A pure yellow flower is crossed with a red flower. 50% of the offspring are yellow 50% of the offspring are red Which allele is dominant? red flower Which allele is recessive? yellow flower What is the genotype of the yellow flower? rr What is the genotype of the white flower? Rr

Rr Two red flowers are crossed. 75 % of the offspring are red 25% of the offspring are white Which allele is dominant? red flower Which allele is recessive? white flower What are the genotypes of the parents (red flowers)? Rr

X INCOMPLETE DOMINANCE ---- has a blending affect. RR WW RW Genotype? pink red white X RR WW RW Genotype?

X CODOMINANCE both alleles are separately expressed. RW RR WW white flower red & white flower red flower X RW RR WW Genotype?

Wavy hair In humans, the allele C (curly hair ) exhibits incomplete dominance over the allele S (straight hair). What type of hair will an individual with genotype CS have? Wavy hair The phenotype would be intermediate between the two.

 Two parents are found to be carriers of a genetic disorder caused by a recessive allele (m). Offspring born with two recessive alleles die before becoming old enough to reproduce. What is the likelihood of these parents having an offspring with the disorder? mm Mm Mm ? X

Codominance or Incomplete dominance

A man with type A blood and a woman with type B blood have a type O child. What are the genotypes of the parents? Man is IAi Woman is IBi