mod 5 iq4&5

allele

variation of a gene

crossing over

the meeting of chromosomes at a chiasmata to exchange genetic information to create new combinations of genes

random segregation

when sister chromatids are separated in meiosis to create genetic variation

independent assortment

separation of homologous chromosomes paternal and maternal to create variation during meiosis

incomplete dominance

when two dominant traits produced proteins that blend to be expressed in a blend of two characteristics

codominance

when two dominant traits are expressed simultaneously.

polygenic traits

traits influenced by 2 or more genes

sex linkage

when an allele is found on the X chromosome. Since the x chromosome holds much more genetic information than the Y chromosome, theres more likely to be a gene found on there. x also masks the y chromosome

heterozygous

2 different alles. Tt

homozygous

2 same alleles. tt

pedigrees

charts used to express family history and where conditions are expressed

polymerase chain reaction

when a fragment of DNA is replicated many times using this lab technique

1. denaturation at 90ºC to break apart the DNA strands

2. DNA primase is added building primers

3. taq polymerase extends these primers

4. end result is thousands of copies of the original DNA strand

• done for the DNA to be analysed

amplification

the replication of DNA many times by PCR

taq polymerase

the enzyme involved in the building of DNA bases during the DNA replication process. gets its first name from the heat-tolerant bacterium

DNA sequencing

finding the precise order of nucleotide bases in DNA

1. cut dn aiwth restriction enzymes

2. amplification by PCR

3. count the number of strs

4. gel electrophoresis

5. look and see

short tandem repeats

the repetition of 1 or more bases 3-6 times often placed at the end of introns. used in DNA profiling

DNA profiling

a lab technique used for forensics and paternal testing. amplifies DNA and separates it into bands that creates DNA fingerprints that can be compared with others

nondisjunction

failure of homologous chromosomes to separate

ddDNA

a type of DNA with an altered molecular structure to prevent further joining of nucleotide bases. fluoresces and terminates

restriction enzymes

cut DNA at specific places by reading the DNA.

• leaves sticky ends which allow different DNA to attach. recombinant DNA ya