Gene system

1. simple Mendelian systems
2. serial gene systems
3. multiple gene systems (同義遺伝子)
4. opositional gene systems (離反遺伝子)
5. modifier systems
6. cytoplasmic systems
7. systems composed of interacting cytoplasmic and chromosomal genes
   Ex. Aquilegia ecalcarata: no spur (spur = calcar)

   × A. vulgalis, × A. canadensis - no spure
   × A. chrysantha, × A. alpina – spur at the probability of 1/16

   → mediated or determined by multiple genes

[ Mendel ]

Mendelian rules or laws (メンデルの法則)

Law of segregation of genes (the first law)

Law of independent assortment (the second law)

Law of dominance (the third law)

Blood type (group) (血液型)

protein blood group antigen: Rh, MN, etc.
sugar-chain blood group antigen: ABO, P, Lewis, etc.

1932 S, Se or secretor: Schiff F, Sasaki (佐々木計はかる)
1935 P (Q or UM): Imamura (今村昌一)
1935 E: Sugishita (杉下尚治)

three genes (A, B and O) on an allele = multiple alleles
on chromosome #9

A, B and C (that is O in the present)

blood typing in transfusion (輸血)

classified I, II, III and IV (corresponding to O, A, B and AB)

classified I, II, III and IV (corresponding to AB, A, B and O), indepdendent of Janský

agglutinogen (antigen) = A and B → antibody = α and β
proposed ABO blood type
1911 proposed double alleles at one locus

Predicted AB type is more than the measured AB type
proposed triple alleles at one locus, based on statistical anaysis

on chromosome #4

combination of antigens M and N → MM, NN and MN types

Mendelian inheritance without dominance - parentage testing

1947 Walsh & Montgomery: discovered S antigen
1951 Levine: discovered s antigen
⇒ renamed MNS(s)

on Chromosome #1 (with Duffy)
D ≈ Rh⁺: antigen-positive (high mmunogenic potential)

Animal blood types

chimpanzee: A and O
western lowland gorilla: only B
eastern lowland gorilla: B and O
mountain gorilla: A and O
Japanese monkey: mostly B

Chromosome cytology (染色体細胞学)

Techniques

Genetics of polyploids

Hormonal regulation of gonadal functions

anterior pituitary 脳下垂体前葉
spermatogenesis 精子生成

mammary gland 乳腺
uterus 子宮
fertilized 着床
placenta 胎盤

Releasing hormones

2-pyrrolidore carboxylic acid

TSH (thyroid-stimulating hormone) 甲状腺刺激ホルモン

Differentiation of hormones: differentiating from common base genes, infering from the resembled structures
Prolactin CM━GH
___┃━━┗┳┛ single peptide
___┗━┳━┛

GH (growth hormone) 成長ホルモン
MTH (mammotrophic hormone) 乳腺刺激ホルモン, GH means MTH on the above figure

           α-chain  β-chain
    CG        92        139
    LH        89        113
    FSH        -        115

α-chains are roughly common between the hormons but β-chains are different

[ reproductive organ ]

Dimorphism (二型性)

Sex determination

Human egg

Mouse

Development of gonads (生殖腺発達)

Emergence of PCG (PCGの発生)

germ plasm: cells gotten germ plasm gather and produce PCG

                                ♂                              ♀                                  
Mesonephros    → epididymis (副睾丸)  degenerate
wolffian duct      → seminal veside,        degenerate
                               vas deferens
müllerian duct    → degenerate (退化)    oviduct, uterus, vagina
urogential sinus →                                  vaginal vestibule,
       (cloaca)                                            clitoris, labia                  

19th    Primordian germ cells
        migration
25-30th Wolffian duct
        appears (形成開始)
37-45th gonadal ridge develops
44-48th Müllerian duct appears
50th    urogenital sinus appears
60th    W.M.V. complete
        ♀                          ♂
                              43-50 testicular cords appear
                              60    sertoli cells appear
                                    degeneration of M. begins
                              65    intestitial cells apper
60-75   formation of vagina   60-75 growth of W
        commences                   fusion labio-scorotal
                                    swelling
75      degenation of W       78    M-degeneration completes
                                    germ cells enter to meiosis
105     prepuce formation     105   prepuce formation
                                    ovary development commences
120                                 uterus completes
160-260 formation of vagina         - growth of external
        completes                     genitalia

Universal sex determination mechanism (性決定機構)

♀ → ♂, ♀
♀ → ♀ only --- Why!

26 ♂ → XY (somatic reproduction)
181♂ → XY

↓

XX XX YY death
_↘ ↗
XX YY
_↙ ↘
XY XY --- XX propagating in this manner

        Normal      ♂XY    ♀XX     ♀XY
                      66     224      203
        Abnormal    ♂XXY   ♀XO    ♀XYY   ♀XY/XYY
                       3       4        1          1

♀XX × XXY♂, XXY♂, XX/XXY/XXXY♂: all testes have no sperm (no ability of reproduction)

        ♂XY ×     XO♀   XO♀   XYY♀   XY/XYY♀
        F1 ♂:♀ =   1/3    0/6     0/6       0/10

⇒ present gene that cancels out the effect of Y and develops ♀ of which sex chromosome is XY?

_____________________albino_____________agouti
P:__CCX^TY (♂) × CCXX (♀) →

Male parent: both somatic and germ cells are normal
Germ cell (XY) - normal testis

Estimate:
F₁__CCXY(♂)_CCXXT(♀)___2♀_________♂________ ♀
____albino____not agouti___ C-var_______agouti_____albino
_____________C-variegated_not CCXX^TY_not CCX^TY_not CCXX
Fact:
F₁_____2n = 40____ 39/40_____2n = 40
_______no Y_______X^TO, X^TX
_______X^TX - master stream
CCXX or CCXO: close to non-disjunction (CCXO)
F₁♂ testis: no germ cells and normal accessory genital glands

⇔ X^TO = ♂, X^TX = ♂

X-chromosome is also mosaically active
Lyonization (= X-inactivation): one fellow of the pair is active → Barr body

mammal: number of Y choromosomes more or equal to 1 tends to becomes male (male or Y has the priority of sex determination)

CCXY(♂) × X^TaX^Ta(♀)

Ta (tabby): hair with a grey or tawny coat mottled with black like a horse, not like a rabbit

→ X^TaY(♂)__X^TaX(♂)__X^TaX^Ta(Ta-var♀)
__abnormal_tabby____ Ta-variegated
⇒ a half of males are tabby and the remainders are abnormal → the sex chromosomes do not determine the sex
X^TaX^Ta used for the experiment showed no chromosomal defect → is this derived from ♂?

S_XR: sex-reversal

X^TaY(♂) AAS_Xr × XX(♀) AA
_____________|
_______AA:AAS_Xr = 1:1__S_xr: the gene that changes from ♀ to ♂
_____________↓
___________XX:XX
___________♀__♀ → ♂
if it is X^TaY(♂), all of the ♀ F₁ become ♂, it is contradict with the result of experiment
if the gene is on sex chromosome and is not on autosome
_________X^sxr × XX
_____________|
__♂ ← XX^Sxr______X^SxrY - different from the experimental results
_______ AA^Sxr × AA
_____________↓
____________XY
AA:AA^Sxr = 1:1 ⇒ Sxr is on the autosome
P____ (♀)X^TaX × (♂)X^TaY or XY
_____________| 17 pairs
F₁____ X^TaX(♀)__XX(♀)__X^TaY__XY
________116_____124____87___115
_________1:______ 1:_____1:____1
therefore, it is normal
XXXY → ♂: Y-chromosome greatly affects the expression of male in general
XO → ♀: XO usually develops female ⇒

AA^SxrXO → ♀
___AAX^TaO(♀) × XYAA^Sxr(♂)
_____________|
___X^TaX_____X^TaY___XO_____________YO
____♀__♂__________AA(♀)_AA^Sxr(♂)
___15__19____48____11_____8_______death
__________________________└ can not form the normal sperm

sex is determined not only by sex chromosome but also by A. S^XR is discovered from various species

Self or non-self recognition (自己と非自己の認識)

Drosera obovata (2n = 30): observed the meiosis →
irregularity of the bivalent chromosome formation of the hybrid

P: 2n = 14 × 2n = 14 →
F₁: 2n = 14 [self-fertilization n = 14(♂), n = 14(♀)] →
F₂: 2n = 28
confrimed by chrysanthemum (Sakamoto), wheat (Kihara), etc.

P: AA × BB n = 7 = A, n = 7 = B (different strains)

→ F₁: AB [AB(♂) × AB(♀)] → F₂: AABB

genome: a minimum set of genes that are required for life

→ genome analysis (Triticum → x = 7 is the standard)

to demonstrate this, a few complemental discoveries are obtained

→ discovered sex chromosome

heteromorphic pair of chromosomes (不等対染色体) = affecting sex determination

Rumex acetosa ♂ 2n = 12 + XX, ♀ 2n = 12 + XY₁Y₂
– also confirmed on diplont
specific pairing type - e.g., Humulus lupulus and H. scandens

aploid (anorthoploid): formed n = 13 (12 + 1) → x = 6 → forming 6 series of aploids
observed aneuploid chromosomes →
dectecting that the dysplasia of sexual organ is induced by the specific chromosome becoming aneuploid the location(s) that determine sex is surveyed

___X-ray cut →

sex abnormality induced by cutting chromosome with different lengths
determining the location that is related to sex abnormlity by the length

→ applying to gene maps on chromosoems

haplont (半数体) during the gametophyte generation
♂ n = 7 + X (large), ♀ n = 7 + Y (small)

Structural changes in chromosomes (染色体の構造変化)

chromosome break
symmetrical intrachanges

inter-arm inversion
intra-arm inversion

asymmetrical intrachanges

inter-arm deletion
intra-arm deletion

symmetrical interchange
asymmetrical interchange

x

unbroken
broken
metaphase configuration
anaphase configuration

chromatid break
isochromatid break
symmetrical intrachange
asymmetrical intrachange
symmetrical interchange
asymmetrical interchange

x

unbroken
broken
rearranged
anaphase configuraiton

Genome (ゲノム)

= coding DNA + noncoding DNA + mitochondrial DNA + chloroplast DNA

Polyploid (倍数体)

Neopolyploid (新倍数体)

Euploidy (真数性)

Minimum: 2n = 4 (we have known)

diploid (2倍体): having twice the basic (haploid) number of chromosomes
triploid (3倍体), tetraploid (4倍体), pentaploid (5倍体), hexaploid (6倍体), octoploid (8倍体)

Aneuploidy (inclucing monosomics and trisomics, s.l.) (異数性)

Autopolyploid (autoploidy, 同質倍数体)

Autotetraploid (同質4倍体)

             Normal meiosis  Abnormal meiosis
    Parents  AA × AA        AA × AA      AA × AA
    Gametes  A--+-A          AA--+-A       AA--+-AA
    Progeny  AA              AAA           AAAA
             Normal diploid  Autotriploid  Autotetraploid
             (fertile)       (sterile)     (fertile)

Allopolyploid (alloploidy, 異質倍数体)

Allotetraploid (異質4倍体)

              AA   BB                        Delayed
                                             diploidy
    Step 1    AB   + (unreduced gamete)      AA       BB
           AA ABB    (triploidy)             AAAA     BBBB
                     = restoration nuculei
           A  ABB                            AA       BB
    Step 2 +  AABB   cf. Segmented           AABB     +
                         alloploidy

Segmental vs genomic alloploidy

Paring: auto – frequent, allo – rare

not belonging to neither autosome (A) or sex chromosome (X, Y)
β = chromosome of heterochromatin?

Polyploids in plants

Plant species: 30-35% (percentages of polyploidy)
Perennials: polyploidy
Trees: not much polyploidy
Annuals: diploidy
Pteridophytes: > 70%

somatic – often
gametic - rare (need 2 steps)

Haploid (半数体)

→ formation of haploid by pollen culture - effective to breed improvement and gene development

Terms: adelophycean (adj.): referring to the inconspicuous phase in the life history of an alga, alternating with the macroscopic (delophycean) phase

Superiority of polyploid (倍数体の優位性)

→ autosome X = 5 (A + B + C + D + E)

Haplotype (ハプロタイプ)

Haplotype network

Fisher, Halane and Wright

used mathematics to combine Mendelian genetics and Darwinian natural selection

sexual selection and mate choice

a core work of the neo-Darwinian modern evolutionary synthesis

The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time

increase in fitness = genetic variance

the primordial soup theory (= Oparin–Haldane hypothesis)

quantitative analysis, e.g., selection coefficient (淘汰係数), k
industrial melanism, k = 0.33-0.50

evolutionary theory and path analysis (path coefficient) -
significance of random genetic drift
1931 "Evolution in Mendelian populations"

1. Genetic drift (in a sub-divided population)
2. Natural selection (within the population)
3. New adaptations by the competition among the sub-populations

discussed by Wright vs Fisher

emphasized the significance of mutation for various genetic diseases

Calculation of allele frequency from genotype frequency

                                     AA        Aa       aa
Genotype frequency  P(AA)   P(Aa)   P(aa)
Allele frequency         P(A) = P(AA) + P(Aa)/2
                                   P(a) = P(aa) + P(Aa)/2
                                   P(A) + P(a) = 1

Mating table
         aA        bB       oO  
aA   a²AA   abAB   aoAO
bB   abAB   b²BB   boBO
oO   aoAO  boBO  o²OO

A: a² + 2ao = 0.4
B: b² + 2bo = 0.2
O: o² = 0.3 ∴ o = 0.548 … (1)
AB: 2ab = 0.1

find out this law separately

Industrial melanism (工業暗化)

Biston betularia: carbonaria form = dark. insularia form = white
1985 dark type = 95% in Manchester (after the industrial revolution)

less than 1% before the revolution

the dark colos is camouflage from predators