Genetics Smartbook 1 Notes

Karyotype

An organized representation of the chromosomes within a cell.

Diploid

A cell that has two sets of chromosomes, with each type of chromosome being a member of a pair.

Locus

The physical location or position of a gene on a chromosome.

Chromatids

The two copies of a chromosome that remain attached after replication, known as sister chromatids.

Sister Chromatids

Pairs of replicated chromosomes that are genetically identical and attached at the centromere.

Centromere

The segment of a chromosome that provides an attachment site for the kinetochore and where sister chromatids join.

Kinetochore

A protein complex bound to the centromere during meiosis and mitosis.

Mitosis

A type of cell division that results in two genetically identical daughter cells.

Meiosis

The type of cell division responsible for producing gametes in eukaryotes, involving two successive divisions.

Synapsis

The event during prophase in meiosis where homologous chromosomes align along their entire length.

Chiasma

The site of crossing over between homologous chromosomes during prophase of meiosis I.

Allele

An alternative form of a specific gene.

Homozygous

An individual with two identical alleles for a trait (e.g., TT, tt).

Heterozygous

An individual with two different alleles for a trait (e.g., Tt).

Recessive

A trait that is masked by another trait but can reappear in subsequent generations.

Gene

The basic unit of heredity that influences an organism's traits.

Genotype

The genetic composition of an individual, represented by the combination of alleles.

Phenotype

The observable traits of an organism.

X-linked genes

Genes located on the X chromosome.

Mendel's Law of Segregation

The separation of homologous chromosomes during meiosis.

Mendel's Law of Independent Assortment

The independent alignment of different homologous pairs during metaphase I.

Probability

The chance that a specific outcome will occur.

Chi-square test

A statistical method used to test a hypothesis based on observed and expected data.

Loss of function allele

An allele that results in a nonfunctional or compromised RNA or protein, typically recessive.

Gain of function mutation

A mutation that leads to the expression of a dominant mutant allele in cells where it is not normally active.

Dominant-negative mutation

A mutation where the product of the dominant allele interacts with the normal allele's product, altering the phenotype.

Haploinsufficiency

A condition where a heterozygous individual shows an abnormal phenotype due to the loss of function of the dominant mutant allele.

Incomplete penetrance

A pattern of inheritance where an allele does not always produce the expected phenotype.

Heterozygote advantage

The phenomenon where a heterozygote has greater reproductive success than either homozygote.

Incomplete dominance

A situation where a heterozygous individual exhibits a phenotype that is intermediate between the two homozygotes.

Codominance

A phenomenon where both alleles are expressed in a heterozygous individual, showing the phenotypes of both homozygotes.