Introduction<\/strong><\/h5>\n\n\n\nGene interactions play a crucial role in determining the traits of an organism. When alleles of the same gene interact, this can result in dominance, incomplete dominance, or co-dominance\u2014collectively referred to as intra-allelic<\/strong> interactions.<\/p>\n\n\n\n However, when different genes influence the same trait and interact with each other, this phenomenon is known as inter-allelic interaction or epistasis<\/strong>. In epistasis, one gene, called the epistatic gene, can mask or suppress the effect of another gene, known as the hypostatic gene. <\/p>\n\n\n\nThese gene interactions often modify the classic Mendelian ratios observed in dihybrid or trihybrid crosses, leading to altered segregation patterns in the F\u2082 generation. Understanding epistasis is essential for interpreting complex inheritance patterns in breeding and genetics.<\/p>\n\n\n\n
In this article, we explore the main types of two-gene epistasis and how they modify the classical 9:3:3:1 Mendelian ratio observed under independent assortment, leading to the following characteristic F\u2082 segregation patterns:<\/p>\n\n\n\n
\n- Independent Assortment (9:3:3:1, No epistasis)<\/a><\/li>\n\n\n\n
- Recessive epistasis (9:3:4)<\/a><\/li>\n\n\n\n
- Dominant epistasis (12:3:1)<\/a><\/li>\n\n\n\n
- Dominant and recessive (inhibitory) epistasis (13:3)<\/a><\/li>\n\n\n\n
- Duplicate recessive epistasis (9:7)<\/a><\/li>\n\n\n\n
- Duplicate dominant epistasis (15:1)<\/a><\/li>\n\n\n\n
- Polymeric gene interaction (9:6:1)<\/a><\/li>\n<\/ul>\n\n\n\n
For each case, we explain the genetic interaction and illustrate it with the corresponding Punnett square to show how these ratios arise.<\/p>\n\n\n\n
\ud83e\udde9 What is a Punnett Square?<\/h5>\n\n\n\n
Punnett square<\/strong> is a simple but powerful diagram used in genetics to predict the possible combinations of alleles in offspring, based on the genotypes of the parents. It helps visualize how genes segregate and combine, making it easier to understand inheritance patterns\u2014including those modified by epistasis.<\/p>\n\n\n\nIn the context of epistatic interactions<\/strong>, the Punnett square does more than show genotypes\u2014it also helps explain how phenotypes<\/strong> arise when two genes interact. That\u2019s why we\u2019ve included a Punnett square for each genetic model<\/strong> presented in this article, to clarify how the ratios like 9:3:4<\/strong>, 12:3:1<\/strong>, or 15:1<\/strong> come about.<\/p>\n\n\n\nBut now let\u2019s go through every genetic model:<\/p>\n\n\n\n
<\/p>\n\n\n\n
Dihybrid ratio (9:3:3:1)<\/h5>\n\n\n\n
A classical example of two genes influencing a single phenotypic trait\u2014comb shape in poultry\u2014was described by Bateson and Punnett. In this case, two independently assorting genes (R and P) determine the type of comb in chickens, producing four distinct phenotypes in the F\u2082 generation in a 9:3:3:1 ratio.<\/p>\n\n\n\n
Trait:<\/strong> comb shape in poultry<\/p>\n\n\n\nPhenotypes<\/strong>: rose comb, pea comb, a single comb and walnut comb.<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- R<\/strong> = Dominant allele for rose comb<\/em><\/li>\n\n\n\n
- r<\/strong> = Recessive allele (no rose comb)<\/li>\n\n\n\n
- P<\/strong> = Dominant allele for pea comb<\/em><\/li>\n\n\n\n
- p<\/strong> = Recessive allele (no pea comb)<\/li>\n<\/ul>\n\n\n\n
Phenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"two.gene](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Comb-shape-in-poultry.jpg\")
<\/figure>\n\n\n\n(Note: “\u2013” indicates the presence of either homozygous dominant or heterozygous allele<\/em>)<\/p>\n\n\n\nHere’s the Punnett square <\/strong>for the dihybrid cross RrPp \u00d7 RrPp<\/strong>, showing both the genotype<\/strong> and the corresponding phenotype<\/strong> in each cell.<\/p>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-12_3_3_1-1.jpg\")
<\/figure>\n\n\n\n<\/p>\n\n\n\n
\n\n\n\n<\/p>\n\n\n\n
Duplicate recessive epistasis (Complementary gene action 9:7)<\/strong><\/h5>\n\n\n\nA classical example of two genes influencing a single phenotypic trait through complementary gene interaction was described in sweet pea flower color. In this case, two independently assorting genes (A and B) are both required to produce purple color. If either gene is homozygous recessive, the result is white flowers. This leads to two phenotypes in the F\u2082 generation in a 9:7 ratio.<\/p>\n\n\n\n
Trait: <\/strong>Flower color in sweet pea
Phenotypes: <\/strong>Purple flower, white flower<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- A = Dominant allele required for pigment production<\/li>\n\n\n\n
- a = Recessive allele; lacks function<\/li>\n\n\n\n
- B = Dominant allele required for pigment production<\/li>\n\n\n\n
- b = Recessive allele; lacks function
<\/strong><\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/color-in-pea-flower.jpg\")
<\/figure>\n\n\n\n(Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele)<\/em><\/p>\n\n\n\nPunnett square (AaBb x AaBb)<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-9_7.jpg\")
<\/figure>\n\n\n\n<\/p>\n\n\n\n
\n\n\n\n<\/p>\n\n\n\n
Dihybrid ratio (15:1) \u2014 Duplicate Dominant Epistasis<\/strong><\/h5>\n\n\n\nA classical example of two genes controlling a single trait by duplicate dominant epistasis is seen in the awn character of rice. In this model, a dominant allele at either locus (A or B) is sufficient to produce the awned phenotype. The awnless phenotype appears only when both genes are homozygous recessive (aabb). This results in a 15:1 phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n
Trait: <\/strong>Presence or absence of awns in rice<\/p>\n\n\n\n Phenotypes: <\/strong>Awned, Awnless<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- A = Dominant allele producing awns<\/li>\n\n\n\n
- a = Recessive allele (no awn function)<\/li>\n\n\n\n
- B = Another dominant allele producing awns<\/li>\n\n\n\n
- b = Recessive allele (no awn function)
<\/strong><\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Awned-rice.jpg\")
<\/figure>\n\n\n\n(Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele;<\/em> Image from: Masoumi et al. (2020). CIGR Journal, 22(2). <\/a>)<\/p>\n\n\n\nPunnett square (AaBb x AaBb)<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-15_1.jpg\")
<\/figure>\n\n\n\n<\/p>\n\n\n\n
\n\n\n\n<\/p>\n\n\n\n
Dihybrid Ratio (13:3) \u2014 Inhibitory Gene Action (Dominant Epistasis)<\/strong><\/h5>\n\n\n\nIn inhibitory gene interaction, also known as dominant inhibitory epistasis, a dominant allele at one locus (I) inhibits the expression of a gene at a second locus (P), regardless of whether that second gene is dominant or recessive. This results in a 13:3 phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n
Trait:<\/strong> Anthocyanin pigmentation (green vs. purple color) in rice
Phenotypes:<\/strong> Green plant, Purple plant<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- I = Dominant inhibitory allele; suppresses pigmentation (green color)<\/li>\n\n\n\n
- i = Recessive allele; no inhibition<\/li>\n\n\n\n
- P = Dominant pigment-producing allele; required for purple color<\/li>\n\n\n\n
- p = Recessive allele; no pigment production<\/li>\n<\/ul>\n\n\n\n
Phenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/rice-leaf-color.jpg\")
<\/figure>\n\n\n\n(Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele; Image adapted from: Ma, X. et al. (2021). Plant Diversity<\/strong>, 43(5), 308\u201331<\/a>)<\/em><\/p>\n\n\n\nPunnett square (IiPp x IiPp)<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-13_3.jpg\")
<\/figure>\n\n\n\n<\/p>\n\n\n\n
\n\n\n\n<\/p>\n\n\n\n
Dihybrid Ratio (9:6:1) \u2014 Additive Factors (Polymeric Gene Action)<\/strong><\/h5>\n\n\n\nIn polymeric gene interaction, also known as additive gene action, two dominant genes (A and B) independently contribute the same phenotype, but when both are present, their effects are cumulative, producing an enhanced phenotype. Each gene shows complete dominance. This results in a 9:6:1 phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n
Trait: <\/strong>Awn length in barley
Phenotypes: <\/strong>Long awns, Medium awns, Awnless<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- A = Dominant allele contributing to awn length<\/li>\n\n\n\n
- a = Recessive allele (no effect on awn)<\/li>\n<\/ul>\n\n\n\n
\n- B = Another dominant allele contributing to awn length<\/li>\n\n\n\n
- b = Recessive allele (no effect on awn)
<\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/awn-length-of-rice-1.jpg\")
<\/figure>\n\n\n\n(Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele; Image source: Luong et al. (2022), The Rice Journal.<\/a>)<\/em><\/p>\n\n\n\nPunnett Square (AaBb \u00d7 AaBb)<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-9_6_1.jpg\")
<\/figure>\n\n\n\n<\/p>\n\n\n\n
\n\n\n\n<\/p>\n\n\n\n
Dihybrid Ratio (12:3:1) \u2014 Dominant Epistasis<\/strong><\/h5>\n\n\n\nIn dominant epistasis, a dominant allele at one gene locus (W) masks the expression of alleles at another gene locus (G). This modifies the classical 9:3:3:1 dihybrid ratio to 12:3:1 in the F\u2082 generation.<\/p>\n\n\n\n
Trait: <\/strong>Fruit color in summer squash
Phenotypes:<\/strong> White, Yellow, Green<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- W = Dominant epistatic allele for white color<\/li>\n\n\n\n
- w = Recessive allele (no epistatic effect)<\/li>\n<\/ul>\n\n\n\n
\n- G = Dominant allele for yellow color<\/li>\n\n\n\n
- g = Recessive allele (no yellow pigment)
<\/strong><\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/summer-squash-color.jpg\")
<\/figure>\n\n\n\n(Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele)<\/em><\/p>\n\n\n\nPunnett Square (WwGg \u00d7 WwGg)<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-12_3_1.jpg\")
<\/figure>\n\n\n\n<\/p>\n\n\n\n
\n\n\n\n<\/p>\n\n\n\n
Supplementary Gene Action (Recessive Epistasis, 9:3:4)<\/strong><\/h5>\n\n\n\nIn supplementary gene action, one dominant gene controls the main phenotypic effect, while the other gene, though dominant, modifies the expression of the first gene without having a visible effect on its own. This interaction leads to a modified phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n
Trait: <\/strong>Labrador coat color<\/p>\n\n\n\n Phenotypes:<\/strong> black coat,brown coat,pigment, no pigment<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n\n- B = dominant allele for black coat color<\/li>\n\n\n\n
- b = recessive allele for brown coat color<\/li>\n\n\n\n
- E = dominant allele allowing pigment deposition<\/li>\n\n\n\n
- e = recessive allele preventing pigment deposition (epistatic to B gene)
<\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Dog-color.jpg\")
<\/figure>\n\n\n\n(Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele)<\/em><\/p>\n\n\n\nPunnett Square (BbEe \u00d7 BbEe)<\/strong><\/h6>\n\n\n\n![\"\"](\"https:\/\/agrosynapsis.com\/wp-content\/uploads\/2025\/05\/Modelo-9_3_4-1.jpg\")
<\/figure>\n\n\n\n<\/div>\n\n\n\nTo wrap up<\/strong>, understanding epistatic F\u2082 segregation ratios is key to interpreting complex genetic interactions and guiding early-generation selection. At AgroSynapsis, we support breeders in identifying the genetic model behind observed phenotypic classes\u2014starting with our free online tool,<\/strong> EpiTrack<\/strong> <\/a>\ud83e\uddec. Recognizing the correct epistatic interaction helps breeders design their breeding populations and choose the right parent lines<\/strong> in a way that ensures achieving the desirable phenotypes by the end of the breeding program.<\/p>\n\n\n\nTry EpiTrack today and let your data drive smarter breeding decisions!<\/strong> \ud83d\ude80<\/p>\n
However, when different genes influence the same trait and interact with each other, this phenomenon is known as inter-allelic interaction or epistasis<\/strong>. In epistasis, one gene, called the epistatic gene, can mask or suppress the effect of another gene, known as the hypostatic gene. <\/p>\n\n\n\n These gene interactions often modify the classic Mendelian ratios observed in dihybrid or trihybrid crosses, leading to altered segregation patterns in the F\u2082 generation. Understanding epistasis is essential for interpreting complex inheritance patterns in breeding and genetics.<\/p>\n\n\n\n In this article, we explore the main types of two-gene epistasis and how they modify the classical 9:3:3:1 Mendelian ratio observed under independent assortment, leading to the following characteristic F\u2082 segregation patterns:<\/p>\n\n\n\n For each case, we explain the genetic interaction and illustrate it with the corresponding Punnett square to show how these ratios arise.<\/p>\n\n\n\n Punnett square<\/strong> is a simple but powerful diagram used in genetics to predict the possible combinations of alleles in offspring, based on the genotypes of the parents. It helps visualize how genes segregate and combine, making it easier to understand inheritance patterns\u2014including those modified by epistasis.<\/p>\n\n\n\n In the context of epistatic interactions<\/strong>, the Punnett square does more than show genotypes\u2014it also helps explain how phenotypes<\/strong> arise when two genes interact. That\u2019s why we\u2019ve included a Punnett square for each genetic model<\/strong> presented in this article, to clarify how the ratios like 9:3:4<\/strong>, 12:3:1<\/strong>, or 15:1<\/strong> come about.<\/p>\n\n\n\n But now let\u2019s go through every genetic model:<\/p>\n\n\n\n <\/p>\n\n\n\n A classical example of two genes influencing a single phenotypic trait\u2014comb shape in poultry\u2014was described by Bateson and Punnett. In this case, two independently assorting genes (R and P) determine the type of comb in chickens, producing four distinct phenotypes in the F\u2082 generation in a 9:3:3:1 ratio.<\/p>\n\n\n\n Trait:<\/strong> comb shape in poultry<\/p>\n\n\n\n Phenotypes<\/strong>: rose comb, pea comb, a single comb and walnut comb.<\/p>\n\n\n\n (Note: “\u2013” indicates the presence of either homozygous dominant or heterozygous allele<\/em>)<\/p>\n\n\n\n Here’s the Punnett square <\/strong>for the dihybrid cross RrPp \u00d7 RrPp<\/strong>, showing both the genotype<\/strong> and the corresponding phenotype<\/strong> in each cell.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n A classical example of two genes influencing a single phenotypic trait through complementary gene interaction was described in sweet pea flower color. In this case, two independently assorting genes (A and B) are both required to produce purple color. If either gene is homozygous recessive, the result is white flowers. This leads to two phenotypes in the F\u2082 generation in a 9:7 ratio.<\/p>\n\n\n\n Trait: <\/strong>Flower color in sweet pea (Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele)<\/em><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n A classical example of two genes controlling a single trait by duplicate dominant epistasis is seen in the awn character of rice. In this model, a dominant allele at either locus (A or B) is sufficient to produce the awned phenotype. The awnless phenotype appears only when both genes are homozygous recessive (aabb). This results in a 15:1 phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n Trait: <\/strong>Presence or absence of awns in rice<\/p>\n\n\n\n Phenotypes: <\/strong>Awned, Awnless<\/p>\n\n\n\n (Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele;<\/em> Image from: Masoumi et al. (2020). CIGR Journal, 22(2). <\/a>)<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n In inhibitory gene interaction, also known as dominant inhibitory epistasis, a dominant allele at one locus (I) inhibits the expression of a gene at a second locus (P), regardless of whether that second gene is dominant or recessive. This results in a 13:3 phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n Trait:<\/strong> Anthocyanin pigmentation (green vs. purple color) in rice (Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele; Image adapted from: Ma, X. et al. (2021). Plant Diversity<\/strong>, 43(5), 308\u201331<\/a>)<\/em><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n In polymeric gene interaction, also known as additive gene action, two dominant genes (A and B) independently contribute the same phenotype, but when both are present, their effects are cumulative, producing an enhanced phenotype. Each gene shows complete dominance. This results in a 9:6:1 phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n Trait: <\/strong>Awn length in barley (Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele; Image source: Luong et al. (2022), The Rice Journal.<\/a>)<\/em><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n In dominant epistasis, a dominant allele at one gene locus (W) masks the expression of alleles at another gene locus (G). This modifies the classical 9:3:3:1 dihybrid ratio to 12:3:1 in the F\u2082 generation.<\/p>\n\n\n\n Trait: <\/strong>Fruit color in summer squash (Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele)<\/em><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n In supplementary gene action, one dominant gene controls the main phenotypic effect, while the other gene, though dominant, modifies the expression of the first gene without having a visible effect on its own. This interaction leads to a modified phenotypic ratio in the F\u2082 generation.<\/p>\n\n\n\n Trait: <\/strong>Labrador coat color<\/p>\n\n\n\n Phenotypes:<\/strong> black coat,brown coat,pigment, no pigment<\/p>\n\n\n\n (Note: \u201c\u2013\u201d indicates either homozygous dominant or heterozygous allele)<\/em><\/p>\n\n\n\n To wrap up<\/strong>, understanding epistatic F\u2082 segregation ratios is key to interpreting complex genetic interactions and guiding early-generation selection. At AgroSynapsis, we support breeders in identifying the genetic model behind observed phenotypic classes\u2014starting with our free online tool,<\/strong> EpiTrack<\/strong> <\/a>\ud83e\uddec. Recognizing the correct epistatic interaction helps breeders design their breeding populations and choose the right parent lines<\/strong> in a way that ensures achieving the desirable phenotypes by the end of the breeding program.<\/p>\n\n\n\n Try EpiTrack today and let your data drive smarter breeding decisions!<\/strong> \ud83d\ude80<\/p>\n\n
\ud83e\udde9 What is a Punnett Square?<\/h5>\n\n\n\n
Dihybrid ratio (9:3:3:1)<\/h5>\n\n\n\n
Gene Function<\/strong><\/h6>\n\n\n\n
\n
Phenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n<\/figure>\n\n\n\n
\n\n\n\nDuplicate recessive epistasis (Complementary gene action 9:7)<\/strong><\/h5>\n\n\n\n
Phenotypes: <\/strong>Purple flower, white flower<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n
\n
<\/strong><\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\nPunnett square (AaBb x AaBb)<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n
\n\n\n\nDihybrid ratio (15:1) \u2014 Duplicate Dominant Epistasis<\/strong><\/h5>\n\n\n\n
Gene Function<\/strong><\/h6>\n\n\n\n
\n
<\/strong><\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\nPunnett square (AaBb x AaBb)<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n
\n\n\n\nDihybrid Ratio (13:3) \u2014 Inhibitory Gene Action (Dominant Epistasis)<\/strong><\/h5>\n\n\n\n
Phenotypes:<\/strong> Green plant, Purple plant<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n
\n
Phenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\nPunnett square (IiPp x IiPp)<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n
\n\n\n\nDihybrid Ratio (9:6:1) \u2014 Additive Factors (Polymeric Gene Action)<\/strong><\/h5>\n\n\n\n
Phenotypes: <\/strong>Long awns, Medium awns, Awnless<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n
\n
\n
<\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\nPunnett Square (AaBb \u00d7 AaBb)<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n
\n\n\n\nDihybrid Ratio (12:3:1) \u2014 Dominant Epistasis<\/strong><\/h5>\n\n\n\n
Phenotypes:<\/strong> White, Yellow, Green<\/p>\n\n\n\nGene Function<\/strong><\/h6>\n\n\n\n
\n
\n
<\/strong><\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\nPunnett Square (WwGg \u00d7 WwGg)<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n
\n\n\n\nSupplementary Gene Action (Recessive Epistasis, 9:3:4)<\/strong><\/h5>\n\n\n\n
Gene Function<\/strong><\/h6>\n\n\n\n
\n
<\/li>\n<\/ul>\n\n\n\nPhenotypes and Genotypes<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\nPunnett Square (BbEe \u00d7 BbEe)<\/strong><\/h6>\n\n\n\n
<\/figure>\n\n\n\n