Unit 10 Genetics Review Flashcards
Dominant
A trait that will appear in the offspring one of the parents contributes it is known as a dominant trait. Only need 1 parent to give that trait for the baby to have it.
Recessive
A trait that will appear in the offspring only if both parents contribute it. Both parents must give this trait to the baby to have it.
Genes
Sections of DNA that code for specific traits such as eye color, hair color, etc.
Alleles
Different versions of that same gene
P generation
The parent generation (P); it’s the first cross between organisms
F1 generation
A cross between the offspring of the P generation (second generation)
F2 generation
A cross between the offspring of the F1 generation (third generation)
If a person is a carrier for a disease what does that mean: Means that the person has…
Heterozygous traits (One uppercase letter and one lowercase letter)
How does a person get a disease that is recessive?
They need both parents to give them the trait; Two lower case letters (rr)
Examples of recessive disorders include:
Albinism
How does a person get a dominant disorder?
They need one parent to give them the trait, One uppercase letter and one lowercase letter, or two uppercase letters
Examples of dominant disorders include:
Huntington’s disease
Genotype
The genes a person carries. An organism’s allele pairs are called its genotype.
Examples of genotypes include:
RR, rr, Bb, Aa, CC
Phenotype
The physical appearance of the person
Examples of phenotypes include:
Green eyes, tall, brown hair, curly hair, etc.
Homozygous
An organism with two of the same alleles for a particular trait is called homozygous
Examples of homozygous traits include:
AA, CC, HH, RR
Heterozygous
An organism with two different alleles for a particular trait is heterozygous
Examples of heterozygous traits include:
Aa, Cc, Hh, Rr
Law of independent assortment states:
Genes for different traits are sorted separately from one another so that the inheritance of one trait is not dependent on the inheritance of another. This happens in meiosis 1.
Example of independent assortment:
Just because you got eye shape from your mother doesn’t mean you will get her eye color or hair color
Law of segregation states:
Each inherited trait is defined by a gene pair. Parental genes are randomly separated to the sex cells so that sex cells contain only one gene of the pair. Offspring therefore inherit one genetic allele from each parent when sex cells unite in fertilization.
Example of segregation:
Chromosomes are divided so that each sperm and egg gets one of each of the 23 chromosomes.
Law of dominance states:
When parents with pure, contrasting traits are crossed together, only one form of trait appears in the next generation. The hybrid offsprings will exhibit only the dominant trait in the phenotype. This is known as the first law of inheritance.
Example of dominance:
When pea plants with round seeds (RR) are crossed with plants with wrinkled seeds (rr), all seeds in F1 generation were found to be round (Rr).