Name Two Pea Plant Traits Studied By Gregor Mendel

Name Two Pea Plant Traits Studied By Gregor Mendeldefine Genotyped

Identify two traits studied in pea plants by Gregor Mendel. Define "genotype" and "phenotype". Explain why a heterozygous pea plant for height displays the dominant phenotype. Specify the genotype of a plant with the recessive phenotype for height. Describe the difference between "Mendelian" and "polygenic" traits. Discuss why females are more likely carriers for color blindness rather than being affected themselves. Identify a polygenic trait in humans. Explain the possible genotypes for blood type "A" and blood type "O" in the ABO blood group system.

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Gregor Mendel, often called the father of genetics, conducted pioneering experiments with pea plants to understand inheritance patterns. Among the traits he studied, two notable ones are seed shape and flower color. These traits were particularly useful because they exhibited clear dominant and recessive patterns, allowing Mendel to propose fundamental genetic principles.

Genotype refers to the genetic makeup of an organism—the specific alleles it carries for a particular trait. Phenotype, on the other hand, is the observable physical or physiological characteristic resulting from the organism's genotype and environmental influences. For example, in pea plants, the genotype might be "Tt" for plant height, where "T" is the dominant allele for tall stature and "t" is the recessive allele for short stature. The phenotype, however, would be tall if the dominant allele is present, regardless of whether the plant is heterozygous or homozygous dominant.

A heterozygous pea plant for height has one dominant and one recessive allele (Tt). Since the dominant allele masks the effect of the recessive one, the plant will display the dominant phenotype—tall stature. This is because dominance is a relationship between alleles where the presence of a dominant allele is sufficient to produce the dominant phenotype.

If a pea plant exhibits the recessive phenotype for height, its genotype must be homozygous recessive, which is "tt". This is because only two recessive alleles will result in the recessive phenotype, as illustrated by the options: (b) tt.

The difference between a "Mendelian" trait and a "polygenic" trait is primarily in their genetic architecture. Mendelian traits are controlled by a single gene with clear dominant and recessive alleles, such as pea seed shape or color. Polygenic traits involve multiple genes contributing to a continuous spectrum of phenotypes, like human height or skin color, where the combined effect results in a range rather than discrete categories.

Females are more likely to be carriers for color blindness because it is an X-linked recessive trait. Females have two X chromosomes, so even if they inherit one affected allele, the second unaffected X chromosome can compensate, preventing the expression of the trait. They are carriers because they possess the allele but do not show symptoms. Males, having only one X chromosome, will express the condition if they inherit the affected allele.

A polygenic trait in humans is skin color, which is influenced by multiple genes affecting melanin production and distribution. The options include (c) Skin color, which demonstrates the additive effect of multiple genes leading to a range of skin tones.

Regarding the ABO blood group system, the possible genotypes for a person with blood type "A" include AA and AO, as both genotype combinations express type A phenotype. For a person with blood type "O," the only possible genotype is OO, since both alleles must be recessive to produce type O blood.

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