Unit 7: How are genes inherited?

Mendel's Laws

Law of Segregation

Law of Independent Assortment

Law of Dominance

A heterozygous trait will hide the presence of another trait for the same characteristic as one is dominant over another.

Each parent gives only one allele to an egg or sperm so the child will have 2 total. This happens in meiosis.

Alleles needed for each trait are passed on to the offspring independently of one another. One trait does not also come with another trait

Meiosis

Similar to mitosis, a sex cell doubles the amount of chromosomes and goes through two rounds of division (instead of one like mitosis) so each of the 4 (or 1 if it is a female) daughter cells have half the amount of chromosomes as the parent cell.

Alleles

A variation of genes that code for the same trait but slightly different colors or things dealing with that trait.

Genotype

Phenotype

The genetic makeup of the organism which is represented by letters on a punnett square.

The appearance of the organism based on its genotype, color of hair, if they have disease or not, ect.

Types of Traits

Types of Traits

Sex-Linked

Autosomal Dominant/Recessive

Trait that is on one of the alleles on the 22 non sex chromosomes. If the trait is dominant the person only needs one allele to express the trait. If it is recessive they need both.

Trait is only on the X chromosome, so males can only have one allele and whatever that allele is they will express it. Females have two XX chromosomes so traits can be dominant or recessive.

Lethal Dominant/Recessive

Co-Dominance/Intermediate Dominance

Heterozygous alleles combine to form a new trait for example if the mother flower is red (RR) and the dad is white (rr) their kid will be pink (Rr) instead of normal dominant allele which just shows the dominant trait.

If a homozygous trait is inherited it will lead to death before birth, either dominant or recessive depending on the gene.