Lab 1 Genetics & Microevolution

Genotype

The genetic composition of alleles of an organism.

Phenotype

The physical expression of the genotype.

Gene

The section of a chromosome carrying information for a character/trait (color/shape).

Homologous Chromosomes

Have same genes in same location, one from each parent.

Locus

The physical location of a gene on the chromosome.

Diploid

Having two sets of chromosomes, one from each parent (normal human cells)

Haploid

Having a single set of chromosomes (gametes)

Allele

A form/variation of a gene, found on chromosomes (Gene=color. Variation=red or blue)

Heterozygous

Different versions/alleles of a gene (Aa)

Homozygous

Identical versions/alleles of a gene (AA or aa)

What allele is expressed in heterozygote?

Dominant

What allele is not expressed in the heterozygote, only in homozygote?

Recessive

Monohybrid Cross

Cross of a single gene (AA X Ah)

Frequency

Part divided by the whole

Pleiotropic

A single gene that influences the expression of other genes

Somatic Cells

All cells, excluding the egg and sperm

Mendelian Trait

When a single gene determines a specific trait/ single gene with 2 alleles

Gametes

Sex-cells

Polyploid

More than 2 sets of chromosomes

Autosomes

22 none-sex chromosomes

Law

A hypothesis that has the same result every test

Microevolution

Change of allele frequency among populations

Has 2 alleles per 1 gene

Diploid

Humans have 46 chromosomes in each of these.

Somatic Cells

Has 23 pairs of homologous chromosomes

Somatic Cell

Number of chromosomes in each gamete

23

Dihybrid

Different alleles of heterozygous genes (Aa Hh)

Polygenic Trait

result of many different genes working together (physical)

The genetic composition of alleles at a gene.

Genotype

The portion of a chromosome that carries the genetic information.

Gene

Chromosomes with the same genes in the same location. One set inherited from mom and one set from dad.

Homologous Chromosomes

The physical place of a gene on the chromosome.

Locus

Having two sets of homologous chromosomes

Diploid

Having a single set of chromosomes

Haploid

How many pairs of homologous chromosomes does a triploid have?

3

A form of a gene

Allele

The genetic notation for the alleles at a gene

Genotype

Two different alleles at a gene

Heterozygote

Two identical alleles at a gene

Homozygote

The mating of two individuals

Cross

Offspring have the same phenotype through all generations. Must be homozygous genotype.

True Breeding

An individual that has the allele for the trait, but the trait is not seen in the individual.

Carrier

The first generation of offspring in a cross

First filial

A cross of a single gene

Monohybrid cross

Diagram used to predict the genotype frequencies of offspring.

Punnett Square

The result of testing a hypothesis many times and getting the same result.

Law

An explanation of a pattern that has been thoroughly tested.

Theory

A guess that is testable.

Hypothesis

Change of allele frequencies among populations. Changes below the species level.

Microevolution

Group of interbreeding organisms

Population

What is the smallest biological unit that evolves?

Population

How many alleles does every diploid individual have for one gene?

2

How many chromosomes do humans have in each somatic cell?

46

How many pairs of homologous chromosomes do humans have in each somatic cell?

23

How many chromosomes do humans have in each gamete?

23

If a diploid fly has 8 chromosomes, how many homologous pairs does it have?

4

If a fish has 22 homologous pairs of chromosomes, how many chromosomes does it have in all?

44

What is is called when there is a change in the genetic makeup?

Mutation

A change in allele frequencies in a population due to some alleles having an advantage in a specific environment.

Natural selection

Change of allele frequencies due to random events.

Drift

Movement of alleles into or out of a population, such as migration.

Gene flow

New individuals arriving/moving into a population

Immigration

The movement of individuals out/leaving a population

Emigration

What two forces in evolution are based on random events?

Mutation and drift

Which two forces in evolution are NOT based on random events?

Natural selection and non random mating

Two genes with heterozygous alleles at both genes

Dihybrid

The mating where two genes are considered and both are heterozygous (AaDd x AaDd)

Dihybrid cross

when each allele in a pair are inherited independently.

Law of segregation

Two alleles from one gene separate independently from the alleles of a second gene.

Law of independent assortment