BIO 101 - Chapter 10 -Patterns of Inheritance

Gene

A segment of DNA that carries the instructions for synthesizing a protein

Genetics

Determine body function and health

Gregor Mendel

Biologist who founded the laws of dominance, segregation, and independent assortment within biology

Locus

the physical location of a gene on a chromosome

Allele

Homologous pair

Two chromosomes that contain the genes for the same traits.

Diploid cells

Have two alleles for each gene

Filial (F1)

the first generation that results from the crossing of two parental lines

Filial (F2)

pertaining to the relationship of children’s children, both sons and daughters, to their grandparents

True-breeding plants

Self-fertilization, yields offspring identical

Hybrid plants

Plants outwardly resemble true-breeders but produce mixed offspring.

Dominant Alleles

Exert their effects whenever they are present.

Recessive Alleles

One whose effect is masked if a dominant allele is also present.

Encodes nonfunctional proteins.

Homozygous dominant

(YY)

Individuals have two dominant alleles for a gene

Heterozygous

individuals have one dominant and one recessive allele.

Homozygous recessive

individuals have two recessive alleles

Monohybrid Cross

Both parents are heterozygous

Punnett Squares

• Show genotype

• Show how alleles separate during mitosis

• summarize meiosis and fertilization

Law of Dominance

When two different alleles are present, only one is dominant and will be expressed

Law of Independent Assortment

The inheritance of one gene doesn’t affect the inheritance of any other gene.

Law of Segregation

Two alleles for each gene are placed in different gametes.

Genotype

consists of the combination of alleles inherited from both parents.

Phenotype

The observable characteristics of an organism

Dihybrid

crosses track the inheritance of two genes at once

incomplete dominance

the heterozygote has an intermediate phenotype. dominant alleles do not mask each other

Codominant alleles

Do not mask each other, more than one allele encodes a functional protein.

Create a double phenotype.

Ex. Human Blood Type

Pleiotropy

one gene has multiple effects on the phenotype. For example, a gene might affect more than one biochemical pathway

Ex. Marfan syndrome

Marfan syndrome

A genetic disorder that changes the proteins that help make healthy connective tissue. It affects the eyes, bones, joints, hearts, and lungs.

Epistasis

occurs when one gene’s product affects the expression of another gene

Ex. albinism

Sex-linked genes

have unique inheritance patterns

Hemophilia

Unable to produce blood clots

Pedigree

Depicts family relationships and phenotypes

Epigenetics

is a field of research that explores how cells adjust gene expression without altering underlying DNA sequence.

Polygenic trait

it is affected by more than one gene