GENETICS BASIC PATTERNS OF INHERITANCE GENETICS RECESSIVE DISORDERS
GENETICS BASIC PATTERNS OF INHERITANCE
GENETICS • RECESSIVE DISORDERS • DISORDER/PHENOTYPE OBSERVED ONLY • WHEN THE INDIVIDUAL HAS NO DOMINANT ALLELES. • NN = HOMOZYGOUS DOMINANT, NO DISORDER • NN = HETEROZYGOUS, NO DISORDER • NN = HOMOZYGOUS RECESSIVE, HAS DISORDER • CYSTIC FIBROSIS, ALBINISM
GENETICS • DOMINANT DISORDERS • REQUIRES PRESENCE OF DOMINANT ALLELE • NN = HAS DISORDER, HOMOZYGOUS DOMINANT • NN = HAS DISORDER, HETEROZYGOUS DOMINANT • NN = NO DISORDER, HOMOZYGOUS RECESSIVE • HUNTINGTON’S DISEASE
GENETICS • PEDIGREES • A MAP OF A FAMILY HISTORY • FOLLOWS AN INHERITANCE PATTERN • A CARRIER HAS BOTH ALLELES BUT PRESENTS THE DOMINANT PHENOTYPE. • INDIVIDUAL CAN PASS ON THE RECESSIVE ALLELE TO THE OFFSPRING. • BY KNOWING FAMILY HISTORY, YOU CAN PREDICT THE FUTURE. • BOY AND GIRL CARRIERS = RECESSIVE • NO CARRIERS = DOMINANT • ONLY GIRL CARRIERS AND NO BOY CARRIERS = SEX LINKED
GENETICS • COMPLEX INHERITANCE • INCOMPLETE DOMINANCE (MIXING) • BOTH ALLELES OFFER SOME CONTROL. • RR = RED R R= WHITE RR = PINK
GENETICS • CODOMINANCE • BOTH ALLELES PRESENT THE PHENOTYPE • GG = GRAY GG = WHITE • GG = BOTH GRAY AND WHITE SHOW IN THE PONY.
GENETICS • POLYGENIC TRAITS • O IS RECESSIVE • MULTIPLE GENES WILL INFLUENCE THE AND ALSO PHENOTYPE (HAIR COLOR, SKIN COLOR, EYE REPRESENTED COLOR, HEIGHT) AS II • MULTIPLE ALLELE TRAITS • A AND B ARE • MORE THAN 2 ALLELE VARIATIONS FOR A GENE. • BLOOD TYPE (A, B, O, AB) DOMINANT • AB IS CODOMINANT
GENETICS • ½ MALE ½ FEMALE • SEX LINKED TRAITS • ALLELES/GENES ARE FOUND ON X OR Y CHROMOSOMES • CALLED SEX CHROMOSOMES. • FOUND MORE FREQUENTLY IN MALES
GENETICS • NONDISJUNCTION • CHROMOSOMES DON’T SEPARATE CORRECTLY DURING MEIOSIS. • THE CHROMOSOMES ON THE LEFT HAVE SEPARATED PROPERLY GIVING A NORMAL SET OF GAMETES. • THE CHROMOSOMES ON THE RIGHT DID NOT SEPARATE PROPERLY GIVING 2 ABNORMAL GAMETES.
GENETICS • TRISOMY 21 = DOWN SYNDROME • 47 CHROMOSOMES • (3 COPIES OF CHROMOSOME #21) • 23 CHROMOSOMES FROM DAD + 24 CHROMOSOMES FROM MOM = 47
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