Download Introduction to Genetics Terms

Introduction to Genetics Terms
Answer Key
1. Heredity: The passing of traits from parent to offspring.
2. Genetics: The study of heredity.
3. Gene: Units of heredity information.
Genes are pieces of DNA that code for a protein.
4. Alleles: Different forms of a gene.
5. Gametes: Reproductive cells such as egg and sperm.
6. Self pollination: When a plant fertilizes itself.
Offspring look like the parent plant.
7. Cross pollination: Pollen from one plant fertilizes the egg of another.
Offspring look different than the parent.
8. True (Pure) breeding: This plant, when self-pollinating, always produces
identical offspring for a trait. Homozygous is
another way to say this.
9. Dominant : Allele that is seen even when present with the recessive form.
10. Recessive: Allele that is seen only when with another recessive form.
11. Homozygous: Two identical alleles for a trait, like “RR” or “rr”.
12. Heterozygous (Hybrid): Two different alleles for a trait, like “Rr”.
13. Genotype: Genetic make-up of an organism. “RR” is a genotype.
14. Phenotype: Physical characteristics of an organism. Being round is a
phenotype.
15. Segregation: Separation of alleles during gamete formation so that one
copy of each gene goes into the egg or the sperm.
16. Independent Assortment: This is when genes for different traits are not
necessarily inherited together. For example, yellow peas can be on either
short or tall plants.
17. Incomplete Dominance: This is when one allele is not completely dominant
over the other allele. For example, red and white flowers producing pink
offspring.
18. Codominant Alleles: This is when both alleles contribute to the
phenotype. For example, chickens that have black and white alleles have
black and white feathers.
19. Multiple Alleles: Some genes are coded for by more than two alleles such
as 3 alleles controlling human blood type. Your type depends on which two
alleles of the 3 possible you get.
20. Polygenic Inheritance: These traits are controlled by the interaction of
several genes. Skin color in humans is polygenic and is most likely controlled
by 4 genes (along with an environmental influence – think about people who
tan in the sun).