Bio

Bio 10th

Heredity

The passing of genetic information from one generation to the next through reproduction

Genetics

The scientific study of heredity

Genes

Segments of DNA that control specific traits in organisms

Allele

Different versions "flavors" of a gene

ex: For the height gene in pea plants you could have a tall version or a short version

Meiosis

process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

Autosomes

Chromosomes that are not directly involved in determining the sex of an individual. ( we have 22 pairs)

Sex chromosomes

One of the 23 pairs of chromosomes in the human, contains genes that will determine the sex of the individual. ( The last pair)

Female Sex chromosomes

XX

Male Sex Chromosomes

XY

Gregor Mendel

Augustinian monk whose experiments in breeding garden peas led to the discovery of inheritance patterns

Law

Describes what will happen

Law of Dominance

When a organism is hybrid ( heterozygous) for a pair of contrasting traits, it only shows the dominant trait. The other trait remains "hidden."

Dominant

The allele that is always expressed

Recessive

The allele that is not expressed in a hybrid individual

Law of Segregation ( and Recombination)

Alleles are separated from each other during gamete formation ( and recombined at fertilization)

Segregatation

Occurs during Meiosis. The process that results in separation of homologous chromosomes and the alleles they carry

Recombination

Occurs during Fertilization. The process that results in new combinations of homologous chromosomes to produce genetically different offspring

Male

XY

Female

Anaphase I

The disjunction of homologous chromosomes

Genotype

genetic makeup of an organism

Phenotype

An organism's physical appearance, or visible traits.

Homozygous

An organism that has two identical alleles for a trait

Heterozygous

An organism that has two different alleles for a trait

BB

homozygous dominant genotype

Bb

heterozygous genotype

bb

homozygous recessive genotype

Punnett Squares show

Likelihood of results, not actual results

Nonmendelian inheritance patterns

Don't follow the rules

Examples: incomplete dominance, codominance, sex-linked traits

Incomplete Dominance

Situation in which one allele is not completely dominant over another allele. The resulting phenotype is "INBETWEEN."

Codominance

A condition in which both alleles for a gene are fully expressed in the phenotype. Co\= See Both

Law of Independent Assortment

Different traits are inherited independently of each other. Traits are Not linked together

Crossing Over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Multiple Alleles

A gene that has more than two alleles

Ex: Blood Types

Type O Blood

ii (recessive)

Type AB Blood

IAIB - Red blood cells have both A & B antigens

Antigen

Chemical nametag that helps the body ( immune system) identify who is supposed to be there and who is an invader

Antibodies

Proteins made by the immune system to recognize and destroy foreign cells

Sex-Linked Inheritance

A pattern of heredity in which traits are transmitted by genes located on the sex chromosomes

Carrier

An individual who heterozygous but healthy. They can however pass the recessive trait on to their offspring.

Healthy female carrier

Individual \#3

Male who has Hemophilia

Individual \#4

Sex linked traits are seen more often in

males because they only have 1 X chromosome

Pedigree

A diagram that shows the occurrence of a genetic trait in several generations of a family.