Biology Unit 6,Part 2

Genetics

The study of patterns involved in passing instructions for development from parents to their offspring

Trait

a genetically determined variant of a characteristic

Hybrid

Offspring of crosses between parents with different traits

Gene

A segment of DNA on a chromosome that codes for a specific trait

Allele

An alternative form of a gene.

principle of dominance

states that some alleles are dominant and others are recessive

Segregation

Separation of alleles during gamete formation

Gamete

sex cell

Probability

likelihood that a particular event will occur

Homozygous

The two factors have the same information from each parent

Heterozygous

The two factors have different information each parent

Phenotype

An organism's physical appearance, or visible traits.

Genotype

The alleles that an organism possesses

Punnett square

diagram showing the gene combinations that might result from a genetic cross

independent assortment

Independent segregation of genes during the formation of gametes

Incomplete dominance

one allele is not completely dominant over the other allele

codomincance

both alleles contribute to the phenotype

Multiple allele

When more than two possible alleles exist for a trait

Polygenic trait

trait that is produced by two or more genes

Genome

All the genetic information in an organism; all of an organism's chromosomes.

Karyotype

A display of the chromosome pairs of a cell arranged by size and shape.

Sex chromosmes

X and Y chromosomes that determine gender

Autosome

Any chromosome that is not a sex chromosome

sex-linked gene

gene located on the X or Y chromosome

Pedigree

A chart or "family tree" that tracks which members of a family have a particular trait

Nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Genomics

study of whole genomes, including genes and their functions

gel electrophoresis

The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel.

Selective breeding

the process of selecting organisms with desired traits to be parents of the next generation

Hybridization

Crossing dissimilar individuals to bring together the best of both organisms

Inbreeding

A selective breeding method in which two individuals with identical or similar sets of alleles are crossed.

Biotechnology

A form of technology that uses living organisms, usually genes, to modify products, to make or modify plants and animals, or to develop other microorganisms for specific purposes.

polymerase chain reaction

technique that allows molecular biologists to make many copies of a particular gene

Recombinant DNA

DNA produced by combining DNA from different sources

Plasmid

small, circular piece of DNA located in the cytoplasm of many bacteria

Genetic marker

alleles that produce detectable phenotypic differences useful in genetic analysis

Transgenic

term used to refer to an organism that contains genes from other organisms

Clone

member of a population of genetically identical cells produced from a single cell