Genetics test 3

Parental Progeny

progeny with the same combo of markers as the parent

You've been getting these terms right!

Null Hypothesis

statement saying your observed data fits a model

P-value below .05

Reject the null hypothesis

P-value above .05

accept the null hypothesis

Chi-squared X^2

amount of deviation from your expected model

linking

genes (alleles)on the Same Chromosome are likely to be inherited together

Linkage Group

a set of linked genes

Genetic Map

shows the order of linked genes and distances between the genes on a chromosome

Genetic Marker

DNA sequence Such as a SNP or repeat

Physical Marker

Phenotype associated w/ a gene locus

recombinant progeny

progeny with a different combo of markers than the parent

Double Crossover

occurs when two chiasmata form, and there is a double exchange between two nonsister chromatids

Genetic Balance

The ratio of Sex Chromosomes to autosomes that controls the amount of Sex-determining gene products

Chromosome Determination

Whether Specific gene product(s) encoded in a Sex Chromosome are present or absent, presence or absence of Sex Chromosome

Mating-type determination

The expression of gene Variants called idiomorphs controls mating

type (in some haploid microbes)

Environmental sex determination

signals from the environment that determine sex ex: day length, temperature, and social cues

Barr Bodies

inactivated X chromosomes; during the blastocyst stage, an X is deactivated in XX mammals

XIST Gene copy

The copy that is expressed to silence the x chromosome and make it the barr body

Mosaicism

mixed phenotype resulting from different genotypes or gene expression levels in the cells of a molecular organism

Mosaic

Cells within an individual have different genotypes

Female

having 2 X chromosomes

Male

The presence of a Y chromosome

SRY

Encodes transcription factor activator, triggering other ones to turn on, making testes, and turning off the making of ovaries

Hemizygous

the presence of only one allele for a characteristic; having one member of a pair of homologous chromosomes rather than two

Codominance

equal amounts of gene product from both alleles; heterozygotes show the dominant and recessive gene at the same time

complete recessive alleles

A null allele doesn't encode a final gene product

complete dominant alleles

A gain-of-function mutation causes increased activity of a gene product

incomplete dominance:

One allele is not completely dominant to the other, with there being a third blended phenotype present

Pheiotrophy

One gene is responsible for multiple traits

Haploinsufficiency

An individual has one dose of a gene product due to having only one functional allele

Threshold effect

when an individual has one dose of a gene product due to having only one functional allele

recessive lethal allele

The presence of two copies of the lethal allele is needed to exhibit a lethal phenotype; it can be homozygous dominant or recessive

dominant lethal allele

Both homozygotes and heterozygotes for a dominant allele display the lethal phenotype

genetic anticipation

when there is an early onset and/or increase in severity/expressivity of a trait in each successive generation

epistasis

One gene (epistatic)masks the phenotype caused by the second gene (hypostatic)

Recessive epistasis

9:4:3

Dominant Epistasis

dominant allele at locus A blocks the phenotypic expression at locus B

Heterogeneous traits

A phenotype results from a mutation in one of several genes

Polygenic

Many genes contribute to the trait

incomplete penetrance

Not all individuals witht he genotype display the expected phenotype

variable expressivity

Individuals have an associated genotype, but the phenotypes differ between individuals

phenotypic plasticity

The environment can change phenotypic expression; example: Crohn's disease

organelle Heredity

mitochondrial DNA mtDNA, and Chlooroplastic cpDNA

maternal affect

The offspring phenotype is under the control of nuclear gene products present in eggs; RNA and protein in ooplasm

Extranuclear inheritance

Transmission of info to offspring occurs through something in the cytoplasm

Heteroplasmy

mitochondria or chloroplasts from different sources and/or of varying genotypes