Genetics Quick Review Mitosis Formation of Body cells, Diploid cells, 2 new identical Daughter cells

Meiosis: formation of gametes, haploid cells, egg & sperm cells, Genetics Quick Review Meiosis: formation of gametes, haploid cells, egg & sperm cells, 4 new daughter cells.

Genetics Gregor Mendel father of Genetics, studied pea plants, identified dominant and recessive traits. Started to develope the Law of segregation

Genetics Dominant & Recessive Genes (alleles) traits, represented by capital & lower case letters. Dominant trait will mask (hide recessive trait if organism has one gene for each trait. Tall trait =T, short trait=t Organism with the genotype TT or Tt will be tall Organism with the genotype tt will be short Geneticist use a punnett square to show probability and possibility of offspring traits.

Dominant and Recessive Traits 1 Gene cross T= tall dominant t= short recessive

F1 generations

Co-dominant Traits Both traits show up usually use 2 capital letters: RR=red (homozygous / pure bred), WW=white homozygous / pure bred), RW= red & white petals (heterozygous / hybred) on flower. Roan cattle red and White fur (RW)

Co-dominant Traits Both traits show up roan cattle has both reddish and white fur .

Incomplete dominance Both traits blend together Usually use 2 capitals 4 O’clock morning rose RR=red WW=white RW=pink

Multiple Alleles BLOOD TYPE A is co-dominant to type B-blood but dominant over type o-blood genotypes for type A-blood are AA or Ao B is co-dominant to type A-blood but dominant over type o-blood genotypes for type B-blood are BB or Bo O-blood is recessive to type A or type B therefore the only genotype type o-blood has is oo, it is the universal donor. AB are codominant to one another therefore the genotype is AB both traits show up, this blood type is the universal recipient.

Blood Type

Creating the gametes for dihydreds

Dihydred cross 2 sets of gene crosses: 2 traits on same gene of passed on together from 1 generation to another

Crossing two co-dominant or incomplete dominant Each parent may only pass on “1 letter(gene) for each of the traits as shown below

Sex chromosomes & linked traits Traits which are on the 23rd pair of chromosomes (the sex determining chromosomes).

sex linked abnormality Color blindness

Sex linked traits

Genetic Testing Testing is often done to check for the wellness of the offspring Amniocentesis Karyotype Chorionic Villi Sampling Pedigree

Figure 14.17 Testing a fetus for genetic disorders

Karyotype

Figure 14.14 Pedigree analysis Attached Earlobes: A recessive trait Widow’s Peak: A dominant trait Pedigree: Map shows the appearance of a trait in a family tree = Female Affected by Trait = Male Affected by Trait = Male Not Affected by Trait = Female not affected by Trait

Hairy Ear Lobes

Albinism

Color Blindness

Polydactyl

Extra Y Male 1: 1000 births Normal in appearance Usually tall Often exhibit aggressive behavior

Trisomy 21 Down’s Syndrome Mental retardation Flattened facial features Thick tongue

Turner’s Syndrome Short webbed neck Do not mature sexually 99% spontaneously aborted

Trisomy 18 Edward’s syndrome Mentally deficient Low set ears Short sternum Growth retardation 1: 8000

Trisomy 13 Patau Syndrome Severe malformations of facial and nervous system mental deficiency 1: 25,000

Klinefelter’s Syndrome Extra X 1: 1000 births Tall Lower intelligance Often infertile male

Cri du Chat Deletion of 5 p Cat like cry feeding problems low birth weight severe cognitive, speech, and motor delays. behavioral problems unusual facial features.