The passing of an inherited trait, such as dimples, from a parent to an offspring is called heredity.
Genes are segments DNA nucleotides that code for proteins. Proteins are made via transcription and translation. The genetic code of DNA is transcribed to make a mRNA. The mRNA then migrates to the cytoplasm via a nuclear pore of the nucleus. Here, the mRNA, tRNA, ribosomes, and amino acids join during a process called translation. The proteins that are formed result in many of the traits manifested by an organism.
Alleles are variations of genes. Genes are made of at least two alleles. In basic genetics, individuals receive on allele from each parent for each trait. Alleles can be dominant or recessive. A dominant allele is the “stronger” variety of a gene, whereas a recessive allele is considered to be “weaker” variety of a gene. Dominant alleles are represented with a capital letter. Recessive alleles are represented with lowercase letters.
Genotypes refer to the allele combinations that an individual contains. Genotypes determine that proteins that are made. Phenotypes are the physical characteristics that result from proteins made.
Genotypes can be homozygous dominant, heterozygous, or homozygous recessive. If homozygous dominant, an individual has a genotype with two dominant alleles and will show the dominant phenotype. If heterozygous, an individual has one dominant and one recessive allele. Because a dominant allele is present, the individual will show the dominant phenotype. Homozygous recessive genotypes contain two recessive alleles. This is the only way that an individual can manifest the recessive phenotype when dealing with basic genetics.