Genetics Exam 1 - Review Flashcards
Review guide with all exam 1 questions
Gene
Segment of DNA that contains the information to produce a functional prodcut-protein
Trait
Characteristic of an organism
Allele
Alternative version of a specific gene (genotype)
Genome
Collection of all the genes
Proteome
Collection of all the protein in an cell type
Homologous Chromosomes / Homologs
Not 100% identical, they are very similar but not identical. One comes from your mom and the other comes from your dad during meiosis I
Sister Chromatids
100% identical in mitosis and meiosis II
Natural selection
When the environment selects for traits/phenotypes that confer greater reproductive success
Morphs
A form of phenotype that varies within a population
Genetic Variation
Genetic differences among members of the same species or different species
Based upon changes in the DNA code (nucleotides changes)
Mendel’s law of segregation
Separation of homologous chromosomes (anaphase I)
homologs
Mendel’s law of independent assortment
Random alignment of different bivalents / homologous chromosomes (metaphase I)
Synaptonemal complex
Links together homologous chromosomes in meiosis I (chromosomes come in for a hug)
Chiasma
Physical structure that is formed when two chromatids cross over
Bivalents
Pair of homologous chromosomes
Dosage compensation
Refers to the phenomenon in which levels of expression of many genes on the SEX CHROMOSOMES is similar in both sexes even though males and females have different pairs of sex chromosomes
Since females have XX they have more genetic material than males which are XY
to compensate, one of the X’s in females will be deactivated and turned into a barr body
Sex-linked inheritance
When the inheritance is linked to the X chromosomes, sex-linked = x linked
Endosymbiosis
Describes a symbiotic relationship in which the symbiote lives inside the host (ex: mitochondria and chloroplasts)
Overdominance
Heterozygous Advantage
When the heterozygous genotype conferees better reproductive success over the homologous genotypes
Incomplete dominance
This pattern occurs when the heterozygote has a phenotype that is the intermediate between the homozygous dominant and the homozygous recessive
Ex. Red = RR, white = rr, pink = Rr
Gene Interaction
The Phenomenon in which the presence of different genes influence the outcome of a single trait
Lethal alleles
When one of the alleles is deadly
Epistasis
When one gene masks another gene
Ex. flower has a recessive allele like cc and pp and it will mask any of the dominant phenotypes (Ppcc will be white)
Pleiotropy
When one gene has multiple effects
Incomplete penetrance
When dominant phenotype is not expressed even though an individual carries a dominant allele
Ex. you carry the polydactyly allele (a dominant allele) but you have a normal number of fingers
Variable Expressivity
Refers to the spectrum of phenotypic expression. Everyone has the same gene but there is a spectrum
Ex. you have polydactyly and you have an extra finger and your brother has 2 extra fingers and sister has 3 extra fingers
Cytoplasmic inheritance
A inheritance of extranuclear DNA
Ex. mitochondria and chloroplasts
Heteroplasmy
The condition of a cell that contains variation in a particular type of organelle
Ex. Plants with white and green have a combination of two different type of chloroplasts
Gene imprinting
A pattern of inheritance that involves a change in a single gene or chromosome during gamete formation. This is a type of epigenetic. The mode in which this occurs is by methylation
Parental leakage
The contribution of mitochondria by the sperm cell to the zygote
Materinal effect
When the genotype of the mother directly dtermines the phenotype of the children
Ex. Snail shell coiling
sinestral = left (d)
dextral = right (D)
Mom=dd and Dad=DD
all offpsring will be Dd and will be sinestral (because mom genotype)
