Genetic terms

*Still remember your DNA & GENE??

GENETIC TERMS

Click on each term to reveal the definition.

dominant & recessive

Genome

homozygous & heterozygous

TRAIT

genotype & phenotype

ALLELE

Done looking at all the terms?

Now let's do some exercise!

FILL IN THE BLANKS by clicking the correct answer

Let say we have two pea seeds, one with a smooth surface and the other is wrinkled. While smooth (S) being the dominant, and wrinkled, (s) is the recessive trait, what is/are the possible:

SS OR ss

Homozygous genotype? _____________ .

SS or ss

Ss

SS or ss

Heterozygous genotype? _____________ .

Ss

Ss

Smooth

Smooth or wrinkled

Homozygous phenotype? _____________ .

Wrinkled

Smooth or Wrinkled

Smooth

Heterozygous phenotype? _____________ .

Next excercise

Wrinkled

Smooth

Smooth or Wrinkled

FILL IN THE BLANKS GAME

Can you guess the hidden words? After guessing, click on the green boxes to reveal the answer.

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Trait

A trait is a characteristic that can be passed from parent to child.Traits can be determined by genes, environmental factors or by a combination of both. Traits can be qualitative (such as eye colour) or quantitative (such as height or blood pressure).

• Other examples of traits:
• Tongue rolling.
• Curly or straight hair.
• Dimples.

Dominant & Recessive

Dominant refers to the trait that is shown when different alleles are present.

• For example, when both alleles of brown and green eyes are present, the trait shown will be brown eyes. So in this case, brown eye is the dominant trait.
• Dominant trait is always represented by a CAPITAL letter
• E.g. B- for brown eyes, T- for tall plant

Recessive refers to the trait that is less expressed when the dominant allele is present.

• Always represented by a lowercase letter that is the same as the letter that represents the dominant allele.
• E.g. b- for green eyes, t- for short plant

Genotype & Phenotype

Genotype refers to the genetic makeup of an organism.

• Or the pair of alleles present in an individual.
• it is represented in the form of letters that represent genes.
• E.g. BB or Bb (for brown eye colour), PP or Pp (for purple flower).

Phenotype refers to the actual outward, observable expression of a trait.

• E.g. Brown eyes, purple flower.

Homozygous & Heterozygous

Homozygous refers to two alleles of a trait that are the same.

• For example, a person who has both alleles for brown eyes (BB) or two alleles for green eyes (bb).

Heterozygous refers to two alleles of a trait that are different.

• For example, a person who has one allele for brown eyes and another allele for green eyes (Bb).

Allele

Allele is a variant/different form of a gene. Let's take the eye colour trait for example. So we have the gene for eye colour, and the variation of that gene would be brown eye allele, blue eye allele, or green eye allele.

Genome

Genome refers to the complete set of genes or genetic material present in a cell or organism.

• In other words, the genome is all the genetic information of an organism, including the DNA materials inside the nucleus and mitochondria.