biol1406 chapter 13

carl correns

first to suggest central role for chromosomes, authored one of the scientific papers announcing rediscovery of Mendel’s work

walter sutton

chromosomal theory of inheritance, based on observations that similar chromosomes paired with one another during meiosis

T.H Morgan’s organism

drosophila melanogaster (fruit flies)

morgan’s discovery

eye-color gene is located on the X chromosome (X-linked)

why white eyed flies in F2 were male

the Y chromosome lacks the eye color gene, so males express recessive X-linked traits

dosage compensation

ensures equal expression of genes from sex chromosomes even though number of chromosomes is different between sexes

autosomes

any chromosome that is not a sex chromosome

genomic imprinting

the phenotype exhibited by a mutant allele depends on which parent contributed the allele to the offspring

deletion of chromosome 15 results

angelman syndrome (mother) and prader-willi syndrome (father)

epigenetic inheritance

a mitotically and/or meiotically stable change in gene function that does not involve a change in DNA sequence

no crossing over results

the chromosomes will carry the parental combination of alleles

creighton and mcclintock experiment

a physical exchange of genetic material accompanied genetic recombination

alfred sturtevant

as physical distance on a chromosome increases, so does the probability of recombination (crossover) occurring between the gene loci

recombination frequency

recombinant progency / total progeny

three-point testcross

determine the order of genes

aneuploidy

gain (trisomy) or loss (monosomy) of a chromosome, the result of nondisjunction (chromosomes don’t separate in meiosis)

pedigree

diagram showing inheritance of traits across generations

STRs (short tandem repeats)

used as molecular markers

SNPs (single-nucleotide polymorphisms)

used for mapping and identification

GWAS (genome-wide association studies)

link SNPs to traits/disesases

PheWAS (phenotype-wide association studies)

link known genetic variants to phenotypes