The combination of alleles at specific gene locations on an organism's chromosomes, representing its genetic constitution, is known as ______. 

The Correct answer is genotype

Key Points

• The genotype refers to the genetic makeup of an organism. It is the combination of alleles at specific gene locations on the organism's chromosomes.
• It determines the hereditary characteristics of an organism and remains unchanged throughout its life.
• The genotype is represented by specific letters or symbols that indicate the alleles present, such as "AA," "Aa," or "aa."
• It is a crucial concept in Mendelian genetics, where traits are understood based on dominant and recessive alleles.
• The genotype interacts with the environment to produce the observable traits or physical expression, known as the phenotype.
• For example, in pea plants studied by Gregor Mendel, the genotype "TT" or "Tt" results in tall plants, whereas "tt" results in short plants.
• The study of genotypes is essential in understanding genetic disorders, inheritance patterns, and evolutionary biology.
• Modern technologies like genotyping and DNA sequencing help scientists analyze genotypes for medical and research purposes.

 Additional Information

• DNA
  • DNA (Deoxyribonucleic Acid) is the molecule that carries the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms.
  • It is composed of two strands forming a double helix structure, discovered by James Watson and Francis Crick in 1953.
  • DNA contains the genetic information in sequences of nucleotides, which include adenine (A), thymine (T), cytosine (C), and guanine (G).
  • While the genotype is the combination of alleles, DNA is the physical medium that stores and transmits genetic information.
• Double Helix
  • The term double helix refers to the structure of DNA, consisting of two strands twisted around each other.
  • It was first described by Watson and Crick based on the X-ray diffraction data produced by Rosalind Franklin.
  • The strands are held together by hydrogen bonds between complementary bases (A pairs with T, C pairs with G).
  • While the double helix is a structural property of DNA, the genotype is about the specific genetic information encoded within the DNA.
• Phenotype
  • The phenotype refers to the observable physical or biochemical characteristics of an organism, such as height, eye color, or enzyme activity.
  • It is influenced by both the genotype and the environment.
  • For example, two plants with the same genotype for height might vary in actual height due to differences in soil quality, water availability, or sunlight exposure.
  • While the genotype is the genetic blueprint, the phenotype represents the expression of that blueprint.