1. GENETICS!
I LOVE PEAS
MAN!
GREGOR MENDEL

2. WOW!!
PEA
TRAITS!

6. mendel's studies

7. Gene - segment of a chromosome that codes for a trait.
since chromosomes come in pairs
genes come in pairs!

8. allele - contrasting forms
green
yellow
tall
short
smooth
smooth
allele - contrasting forms
of a gene.

9. have lower case letters
are represented
by using letters!
alleles-
DOMINANT ALLELES -
HAVE CAPITOL LETTERS
recessive alleles -
have lower case letters

10. for example...
earlobes
F = free earlobes
f = attached earlobes

11. REMEMBER!!
SINCE GENES COME
IN PAIRS....
ALLELES COME
IN PAIRS!!

12. If both alleles are
DOMINANT =
homozygous DOMINANT!
AA, MM, RR
If both alleles are
recessive =
homozygous recessive!
aa, mm, rr

13. 2 DiFfErEnT AlLeLeS =
hEtErOzYgOuS
eX - Aa, Mm, Tt

14. GENOTYPE PHENOTYPE IS THE LETTER SYMBOLS OF THE ALLELES (MM, Mm, mm)
The physical trait - that you see
big, short, green yellow, widows peak, etc)

15. Monkey toe! M = monkey toe m = normal 2nd toe monkey toe!
Photo courtesy of : Alex Reinke
monkey toe!
normal 2nd toe!
MM =
mm =
monkey toe!
Mm =

16. is a tool used to predict the genotypes and phenotypes of offspring
monohybrid crosses
is a tool used to predict
the
genotypes and phenotypes
of offspring
based on probability

27. Two types of chromosomes are autosomes and sex chromosomes.
Autosomes (#’s total) are chromosomes not involved sex determination.
Sex chromosomes (23rd pair) either XX or XY directly involved in sex determination

28. Sex linked traits refers to traits that are carried on the sex chromosomes. Typically sex linked traits are carried on the X chromosome.

29. H = no hemophilia
h = hemophilia

30. X-inactivation Female mammals inherit 2 X chromosomes XH XHXh Xh
one X becomes inactivated during embryonic development
condenses into compact object = Barr body
which X becomes Barr body is random
patchwork trait = “mosaic”
patches of black
XH
XHXh
Xh
tricolor cats can only be female
patches of orange

31. Multiple allele traits
Traits that are controlled by 3 or more alleles of the same gene (blood grouping is controlled by A, B or O alleles

36. Traits that are controlled by several genes (skin, eye, hair color)
Polygenic traits
Traits that are controlled by several genes (skin, eye, hair color)
AaAAaaAa = 4 genes but 2 alleles (A or a)
polygenic has several genes influencing a trait, multiple allele has several alleles influencing a trait.

40. AUTOSOMAL
DOMINANT

41. Autosomal DOMINANT disorder Disorders carried on the autosomes, controlled by a dominant allele (therefore you only need one dominant allele to show the disorder)

42. AUTOSOMAL
recessive

43. Autosomal recessive disorder Disorders carried on the autosomes, controlled by a recessive allele (therefore you need two recessive alleles to show the disorder)

44. Chromosomal Abnormalities
Nondisjunction
chromosomes don’t separate properly during meiosis
Chromosomal Mutations
deletion
duplication
inversion
translocation

45. Changes in chromosome structure
deletion
loss of a chromosomal segment
duplication
repeat a segment
inversion
reverses a segment
translocation
move segment from one chromosome to another
error of replication
error of crossing over

46. Autosomal Disorders Dominant Recessive Acondroplasia Acromegaly
Dwarfism
Lethal in homozygous cond.
Acromegaly
Gigantism
Overactive pituitary
Huntington’s
Degeneration of nervous system
Manifests around 40 years of age
Recessive
Albinism
Melanin pathway mutated
photosensitivity
Phenylketoneuria
Cannot break down phenylalanine
Lead to mental retardation
Cystic fibrosis
Cl- channel problem
Mucus buildup
Death around 40

47. Nondisjunction Cause of aneuploidy (wrong chromosome #) trisomy
cells have 3 copies of a chromosome
monosomy
cells have only 1 copy of a chromosome
n+1 n n
n-1
trisomy
2n+1
monosomy
2n-1

50. Down syndrome
Trisomy 21
3 copies of chromosome 21
1 in 700 children born in U.S.
Chromosome 21 is the smallest human chromosome
but still severe effects
Frequency of Down syndrome correlates with the age of the mother
Trisomy 13 occurs in about 1 out of every 5,000 live births. It is a syndrome with multiple abnormalities, many of which are not compatible with life. More than 80% of children with trisomy 13 die in the first month. Trisomy 13 is associated with multiple abnormalities, including defects of the brain that lead to seizures, apnea, deafness, and eye abnormalities. The eyes are small with defects in the iris (coloboma ). Most infants have a cleft lip and cleft palate, and low-set ears. Congenital heart disease is present in approximately 80% of affected infants. Hernias and genital abnormalities are common.
Trisomy 18 is a relatively common syndrome affecting approximately 1 out of 3,000 live births, and affecting girls more than three times as often as boys. The presence of an extra number 18 chromosome leads to multiple abnormalities. Many of these abnormalities make it hard for infants to live longer than a few months.
The cri du chat syndrome is caused by the deletion of information on chromosome 5. It is likely that multiple genes on chromosome 5 are deleted. One deleted gene, called TERT (telomerase reverse transcriptase) is involved in control of cell growth, and may play a role in how some of the features of cri cu chat develop. The cause of this rare chromosomal deletion is not known, but it is expected that the majority of cases are due to spontaneous loss of a piece of chromosome 5 during development of an egg or sperm. A minority of cases result from one parent carrying a rearrangement of chromosome 5 called a translocation. Between 1 in 20,000 and 1 in 50,000 babies are affected. This disease may account for up to 1% of individuals with severe mental retardation. Infants with cri du chat syndrome commonly have a distinctive cat-like cry. They also have an extensive grouping of abnormalities, with severe mental retardation being the most important.

51. Down syndrome & age of mother
Mother’s age
Incidence of Down Syndrome
Under 30
<1 in 1000 30
1 in 900 35
1 in 400 36
1 in 300 37
1 in 230 38
1 in 180 39
1 in 135 40
1 in 105 42
1 in 60 44
1 in 35 46
1 in 20 48
1 in 16 49
1 in 12

52. Sex Chromosomes Abnormalities
Human development more tolerant of wrong numbers in sex chromosome
Cause is nondisjunction
But produces a variety of distinct syndromes in humans
XXY = Klinefelter’s syndrome male
XXX = Trisomy X female
XYY = Jacob’s syndrome male
XO = Turner syndrome female

53. Non-disjunction – failure of homologous chromosomes to separate during meiosis. Results in an aneuploidy
Karyotype – Picture of a person’s chromosomes in a somatic cell. Used to detect genetic disorders.
Amniocentesis – removal of amniotic fluid and analyze the chromosomes in the cells

54. Rate of miscarriage due to amniocentesis:
1970s data 0.5%, or 1 in 200 pregnancies
2006 data <0.1%, or 1 in 1600 pregnancies

55. Pedigree Analysis
A pedigree is a family tree that describes the interrelationships of parents and children across generations
Inheritance patterns of particular traits can be traced and described using pedigrees

56. = FEMALE
= MALE
= FEMALE WITH TRAIT
= MALE WITH TRAIT OR
= DECEASED

57. = MARRIAGE LINE
= CHILD LINE

58. 1 2 3 4 I II
III
Generation #

59. 1 2 3 4 I II
III
Individual #

60. I II III When describing a person, you write the Generation #
a dash (-) then the
individual number 1 2 3 4 I II
III
For example, II - 2
shows the trait or
II-1 is the oldest child
of the original parents

61. this pedigree shows the occurance of attached earlobes! (shaded in)1 2 3 4 I II
III
Earlobes
E = Free earlobes
e = attached earlobes
what is genotype of I-2?
what is genotype of I-1?
Can II-1 be
homozygous dominant?
this pedigree shows the occurance of attached earlobes! (shaded in)

62. draw a pedigree!! lets play ... a mother and a father have 6 kids
the first 2 are boys as well
as the youngest. the other 3 are girls.
the last male
married a woman and has 8 girls.

63. 1 2 3 4 I II
III
predict genotypes
for all individuals