Genetics Final Vocab

alleles

different versions of a gene

cytokinesis

the process of division of one cell to produce two daughter cells (occurs during telophase)

phenotype

the observable properties of an individual

incomplete dominance

when heterozygotes show a phenotype intermediate between either of the two homozygotes

centromere

serves to hold sister chromatids together and provides the point of attachment for the spindle during cell division

hemizygosity

having one copy of some genetic region, such as much of the X chromosome in males

somatic cells

the cells that make up most of the body; all cells besides germ cells

pleiotropy

where mutation in one gene produces multiple traits

synapsis

pairing of homologous chromosomes during meiosis I

nondisjunction

where the chromosomes fail to properly segregate from one another during mitosis or either meiotic division

intercalators

a class of chemicals that produces mutations by inserting between adjacent base pairs of DNA

epistasis

when the phenotype expected from one gene is dependent on the genotype of another gene

linkage

the tendency for genes located on the same chromosome to be inherited together

telocentric

a chromosome in which the centromere is located at an end

conservative mutation

a mutation that leads to production of a protein in which one amino acid is replaced by a biochemically similar one

null mutation

a mutation that completely eliminates gene function

sex-influenced

traits that are seen in both males and females but are more severe in one sex than the other

holocentric chromosome

where the kinetochore assembles along the length of the chromosome

X chromosome inactivation

the process by which one of the two X chromosomes in XX female mammals is largely shut down; the purpose is to balance gene expression on the X chromosome between males and females

epigenetics

heritable state of gene function not encoded within the sequence of the DNA

merodiploid

a bacterial cell that is diploid for a portion of its genome

conjugation

the exchange of DNA between bacterial cells that involves direct contact between participating cells

monoploid

an organism with onl one copy of each chromosome

Northern blotting

the procedure whereby RNA is separated by agarose gel electrophoresis, transferred to membrane and incubated with a specific probe

Cri du chat

a disorder characterized by severe intellectual disability and a cat-like cry; it results from deletion of a portion of the short armk of chromosome 5

balanced chromosomal complement

where no DNA is present in excess or missing from the chromosomal complement (i.e. there are exactly two copies of the genetic info. in a diploid)

aneuploid

a cell or individual with some deviation from a whole multiple of the haploid or monoploid chromosome compliment (i.e. having one extra chromosome or missing one chromosome)

lysogen

a bacterial cell that harbors a phage genome within its chromosomal DNA

endosymbiont

an organism, usually prokaryotic, residing within the cytoplasm of a host cell

endopolyploidy

having extra sets of chromosomes in some cells of the body

single nucleotide polymorphism (SNP)

variation of a specific single nucleotide (i.e. the same/corresponding base) between individuals

genetic anticipation

the phenomenon whereby some disorders get worse in subsequent generation; it results from the tendency of DNAP to slip at repeated sequences

subpopulation

a distinct breeding group within a larger interbreeding group of individuals

paralogs

genes that arise by duplication within a species

autopolyploidy

an individual having multiple copies of each chromosome, all derived from the same original species

apoptosis

the genetic program that is used to eliminate excess cells or cells that may become cancerous

pseudoautosomal region

chromosomal region found on both the X and Y chromosomes

metastasis

spread of cancerous cells

gain-of-function mutation

a mutation in which the gene acquires some new activity

multifactorial traits

traits that are specified by multiple genes, often in conjunction with environmental inputs

checkpoint

a point where the cell can halt its progress through the cell cycle ( i.e. in the event of DNA damage or unattached chromosomes)

tumor suppressors

a class of genes whose products tend to protect cells from becoming cancerous; in cancer, mutations in these genes are typically recessive

induced pluripotent stem cells

cells that appear capable of becoming any cell mtype and of extended proliferation, making them potentially clinically useful for treating some types of disorders

retrotranspon

a mobile DNA element that moves through an RNA intermediate

equivalence group

a group of cells with equivalent developmental potential

haploinsufficient

refers to the situation where having one WT copy of a gene is not sufficient to prevent a mutant phenotype