UNH Gen 604 Exam 1

Reductionism

Breaking complex things into simpler parts for better understanding.

Mutation

A process that gives rise to mutants.

Forward Genetics

Starting from a pool of random single-gene mutants and finding mutants with phenotypes of interest.

Mendel's Law of Equal Segregation

One allele for each gene is contributed to the gamete, with an equal chance of contributing either allele.

Monohybrid

Heterozygotes for a single gene.

Dihybrid

Heterozygotes for two genes.

Mitosis

A process where a cell divides to produce two identical daughter cells.

Meiosis

A process during the sexual cycle that produces meiocytes that become gametes.

Alleles

Different versions of the same gene.

Haplosufficiency

One functional allele is enough to produce the wild-type phenotype.

Haploinsufficiency

One functional allele is not enough to produce the wild-type phenotype.

Sex Chromosomes

Chromosomes that determine the sex of an organism.

X-linked Recessive

A trait usually present in males, passed from affected males to daughters as carriers.

X-linked Dominant

Affected males pass the condition to all daughters but no sons.

Y-linked Inheritance

Inheritance of genes located on the Y chromosome, such as the SRY gene determining maleness.

Independent Assortment

The heritability of one gene does not affect the heritability of another.

Recombination

The production of new allelic combinations due to independent assortment or crossing over.

Quantitative Trait Loci (QTL)

Genes that control continuous (quantitative) traits.

Maternal Inheritance

Mitochondrial and chloroplast DNA are inherited from the mother.

Linkage

Genes located on the same chromosome that tend to be inherited together.

Recombination Frequency

The percentage of recombinant offspring, used to measure genetic distance.

Genetic Map Units (cM)

A unit measuring the distance between genes, where 1% recombination equals 1 centimorgan.

Molecular Markers

Sequence variants used to map genes to chromosomal locations.

Chi-square Test

A statistical test used to determine if observed genetic ratios deviate from expected ratios due to chance.

Pedigree Analysis

The study of family inheritance patterns to determine the genetics of a trait.

Autosomal Recessive

A trait that appears in progeny of unaffected parents, often seen in both sexes.

Autosomal Dominant

A rare allele that is dominant, meaning only one copy is needed for the phenotype to appear.

Dimorphisms

Polymorphisms that give rise to alternative common morphs, such as blue vs. brown eyes.

Polygenic Inheritance

Traits controlled by multiple genes rather than a single gene.

Cytoplasmic Segregation

The process where different organelle genotypes segregate as cells divide.

Chiasmata

Physical chromosome conformations that give rise to crossing over during meiosis.

Map Units

A measurement of genetic distance based on recombination frequency.

Double Crossovers

Rare recombination events where two separate crossover events occur within the same chromosome pair.

Reciprocal Cross

A genetic cross where the phenotypes of the male and female parents are switched to test inheritance patterns.

Single Nucleotide Polymorphisms (SNPs)

Genetic variations at a single nucleotide position, used as molecular markers.

Microsatellite Markers

Short tandem repeat sequences used as molecular markers in genetic mapping.

Trihybrid Cross

A cross between individuals heterozygous for three genes, often leading to an 8-class phenotypic ratio.

Segregation Ratios

The expected ratios of offspring phenotypes based on inheritance laws.

Hybrid Vigor

When hybrid offspring show improved traits compared to their purebred parents.

Homozygous

Having two identical alleles for a gene.

Heterozygous

Having two different alleles for a gene.

SRY Gene

A Y-linked gene responsible for male sex determination.

Dominant Mutation

A mutation that produces a phenotype when present in a single copy.

Null Mutation

A mutation that completely inactivates a gene's function.

Centromere

The part of a chromosome that links sister chromatids and is essential during cell division.

Telophase

The final phase of mitosis and meiosis where the nuclear envelope reforms around separated chromosomes.