Mendel studied several different traits possessed by pea plants such as seed color, seed texture, and overall plant height. When Mendel cross-pollinated his pea plants creating hybrids, he began to make some further discoveries. This brought on Mendel's first conclusion that an individual's characteristics are determined by the factors or traits that are passed down from one generation of parents to the next. Pea plants usually self-fertilize by possessing both the male and female sexual reproductive organs, and therefore produce identical offspring because all the genetic information comes from the same parent. While working in the garden Mendel experimented with cross-pollinating pea plants. He was an Austrian monk who was responsible for maintaining his monastery's garden. Gregor Mendel is considered the Father of Genetics. Gregor Mendel and Plant Traits from Parents For example, a cow with white fur bred with a cow with reddish fur can produce offspring with spotted white and reddish fur (where both fur phenotypes are present on the offspring). A co-dominant genotype produces a phenotype where both the allele phenotypical traits are exhibited. Co-dominance occurs between alleles where both or all the alleles are dominant alleles.
Green, hazel, or brown eyes are dominant alleles because their presence negates the presence of the recessive alleles for blue eyes.Īlleles can also be co-dominant. Whereas heterozygous genotypes composed of any alleles that result in additional pigment in the iris at all, would subsequently produce a phenotype with at least some iris pigment and therefore not be blue eyes (the lack of pigment). If any of the alleles are dominant, the recessive alleles are merely carried in the genotype.īecause blue eyes in humans is a recessive trait, the child in this image must have a homozygous recessive genotype for eye color.įor example, blue eyes are recessive in humans because they emerge from a genotype that results in a lack of pigment in the irises of the person's eye. Recessive alleles can only emerge as the phenotype if all the alleles within the genotype are the same recessive trait i.e., homozygous recessive. Dominant alleles emerge as the phenotype as long as at least one is present in the genotype. There are dominant and recessive alleles. What determines the organism's phenotype is contingent on the dominant and recessive relationship between its alleles for that given trait. A person can have alleles for different eye colors, and only present one eye color as their phenotype. For example, human eye color is determined by more than one gene each composed of more than one allele. Heterozygous genotypes are composed of varying alleles (for example, "Aa").Ī given genotype is composed of alleles that can all vary in their respective phenotypes. Homozygous genotypes are composed of alleles that are all the same (for example, "aa"). Genotypes can be homozygous or heterozygous. The phenotype is the physical manifestation of an organism's genotype.
#Genotypes of dominant traits code
A genotype is the genetic code or set of alleles within a gene or group of genes that emerge as a phenotype.
Offspring from the same parents can vary in their physical characteristics or phenotype because their genotypes can vary.
There are different versions of each gene called alleles. Offspring from parents obtain a selection of genetic information packed into chromosomes from each parent, called genes. Offspring from the same parents can vary because each gamete, or sex cell (such as sperm or egg) is genetically unique. One of the few mechanisms that drives the evolution of species is sexual reproduction and genetic variation amongst offspring. How Alleles Are Passed from Parents to Offspring
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