AP BIO UNIT 5 VOCAB

Allele

Any of the alternative versions of a gene that may produce distinguishable phenotypic effects

Asexual Reproduction

The generation of offspring from a single parent that occurs without the fusion of gametes. In most cases, the offspring are genetically identical to the parent

Autosomes

A chromosome that is not directly involved in determining sex; not a sex chromosome

Carriers

In genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder.

Chiasma

The x-shaped microscopically visible region where crossing over has occurred earlier in prophase I between homologous nonsister chromatids

Clone

A lineage of genetically identical individuals or cells

Crossing over

The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis

Diploid cell

A cell containing two sets of chromosomes, one set is inherited from each parent

Heterozygous

Having two different alleles for a given gene

Hybridization

The mating, or crossing, of two true-breeding varieties

Homozygous

Having two identical alleles for a given gene

Fertilization

The union of haploid gametes to produce a diploid zygote

Karyotype

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

Law of independent assortment

Mendel's second law, stating that each pair of alleles segregates, or assorts, independently of each other pair during gamete formation

Genotype

The genetic makeup, or set of alleles, of an organism

Haploid Cell

A cell containing only one set of chromosomes

Law of Segregation

Mendel's first law, stating that the two alleles in a pair segregate into different gametes during gamete formation

Linked Genes

Genes located close enough together on a chromosome that they tend to be inherited together

Locus

A specific place along the length of a chromosome where a given gene is located

Meiosis

A modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cell

P Generation

The true-breeding parent individuals from which F1 hybrid offspring are derived in studies of inheritance. P stands for parental

Pedigree

A diagram of a family tree with conventional symbols, showing the occurrence of heritable characters in parents and offspring over multiple generations

Phenotype

The observable physical and physiological traits of an organism, which are determined by its genetic makeup

Recessive Allele

An allele whose phenotypic effect is not observed in a heterozygote

Recombinant Chromsomes

A chromosome created when crossing over combines DNA from two parents into a single chromosome

Sex Chromosomes

A chromosome responsible for determining the sex of an individual

Sexual Reproduction

A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from both parents via the gametes

Synapsis

The paring and physical connection of duplicated homologous chromosomes during prophase I of meiosis

Trait

One of two or more detectable variants in a genetic character

True Breeding

Referring to organisms that produce offspring of the same variety over many generations of self-pollination

Variation

Differences between members of the same species

Wildtype

The phenotype most commonly observed in natural populations

Zygote

The diploid cell produced by the union of haploid gametes during fertilization