Video Summary - [5단원.생식과 유전]5-16.유전 용어-2

Scientific concepts and nature/genetics phenomena mentioned

Dominance principle: some allele variants can mask others in phenotype expression.
Law of segregation: alleles separate into gametes during meiosis, so each gamete carries one allele per gene.
Law of independent assortment: mentioned for context (mechanism not detailed in this excerpt).

Phenotype: outwardly visible traits, such as:
- Round vs. wrinkled seed shape
- Yellow vs. green seed color
Genotype: the allele composition (typically represented using letters), including:
- Dominant vs. recessive allele notation

Dominant alleles are written with uppercase letters.
Recessive alleles are written with lowercase letters.
Example pea seed traits:
- Round seed shape = dominant
- Wrinkled seed shape = recessive
- Yellow seed color = dominant
- Green seed color = recessive

Purebred (true-breeding): consistently produces the same trait after self-pollination; corresponds to a homozygous genotype (two identical alleles).
Hybrid: has different alleles for a trait; corresponds to a heterozygous genotype.

Assign:
- Dominant allele (round) with an uppercase letter
- Recessive allele (wrinkled) with a lowercase letter
Genotype outcomes:
- AA (two dominant alleles) → purebred round phenotype
- aa (two recessive alleles) → purebred wrinkled phenotype
- Aa (one dominant + one recessive) → hybrid with dominant phenotype expressed (round)

Assign:
- Yellow = dominant allele (uppercase)
- Green = recessive allele (lowercase)
Genotype outcomes:
- YY (two dominant alleles) → purebred yellow phenotype
- yy (two recessive alleles) → purebred green phenotype
- Yy (one dominant + one recessive) → hybrid with yellow phenotype expressed (dominance of yellow)
Key mechanism mentioned:
- During meiosis, gametes carry only one allele for a gene; after fertilization, the offspring forms a pair of alleles again.