Reg Unit 10: Who am I

Meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

homologous chromosomes (pair)

Chromosomes that have the same sequence of genes and the same structure

Crossing over/recombination

exchange of genetic material between homologous chromosomes

Nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Karyotype

A picture of all the chromosomes in a cell arranged in pairs

sex chromosomes

Chromosomes that determine the sex of an individual X and Y)

Gamete

sex cell created during meiosis

genetic diversity

the variety of genes within a given species

sexual reproduction

Process by which cells from two different parents unite to produce the first cell of a new organism.

autosome

Any chromosome that is not a sex chromosome

Fertilization

Fusion of an egg and sperm cell

Haploid

having a single set of unpaired chromosomes

Diploid

2 sets of chromosomes

independent assortment

One of Mendel's principles that states that genes for different traits can segregate independently during the formation of gametes

Zygote

a diploid cell resulting from the combination of two haploid gametes; a fertilized egg.

Trait

A characteristic that an organism can pass on to its offspring through its genes.

Gene

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

Alelle

Different versions of a trait/gene

Genotype

An organism's allele combinations; one allele from each parent

Phenotype

An organism's physical appearance, or visible traits.

Heterozygous (hybrid)

An organism that has two different alleles for a trait

Homozygous (purebred)

An organism that has two identical alleles for a trait

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

recessive allele

An allele that is hidden when the dominant allele is present

monohybrid cross

A cross between individuals that involves one pair of traits

monogenic traits

Traits determined by a single gene.

polygenic traits

traits controlled by two or more genes

Pedigree

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

Carrier

A person whose genotype includes a gene that is not expressed in the phenotype.